Improvement
of biological activity by low energy ultrasound assisted bioreactors. Schlafer
O, Sievers M, Klotzbucher H, Onyeche TI. Ultrasonics 2000 Mar;38(1-8):711-6.
Clausthaler
Umwelttechnik-Institut, Clausthal-Zellerfeld, Germany.
RESULTS:
An increase in the biological activity of the process investigated with alternating
ultrasound as well as a decrease without ultrasound were measured. Application
of ultrasound to biotechnology: an overview. Sinisterra JV. Ultrasonics 1992;30(3):180-5
Organic and Pharmaceutical Chemistry Department, Faculty of Pharmacy, Universidad
Complutense, Madrid, Spain. Application of ultrasound to biotechnology is relatively
new, but several processes that take place in the presence of cells or enzymes
are activated by ultrasonic waves. High intensity ultrasonic waves break the cells
and denaturize the enzymes. Low intensity ultrasonic waves can modify cellular
metabolism or improve the mass transfer of reagents and products through the boundary
layer or through the cellular wall and membrane. In the case of enzymes, the increase
in the mass transfer rate of the reagents to the active site seems to be the most
important factor. Immobilized enzymes are more resistant to thermal deactivation
produced by ultrasound than native enzymes. Reverse micelles can be used to carry
out synthesis using enzymes. Several applications of ultrasound to the biotechnology
are discussed. Synergistic effect of low-frequency
ultrasound and surfactants on skin permeability. Tezel A, Sens A, Tuchscherer
J, Mitragotri S. J Pharm Sci 2002 Jan;91(1):91-100
Department
of Chemical Engineering, University of California Santa Barbara, Santa Barbara,
California 93106, USA.
RESULTS: The experiments show
that ultrasound enhances surfactant delivery and dispersion in the skin.
Intracellular drug delivery using low-frequency ultrasound: quantification
of molecular uptake and cell viability. Keyhani K, Guzman HR, Parsons A, Lewis
TN, Prausnitz MR. Pharm Res 2001 Nov;18(11):1514-20
School
of Chemical Engineering, Georgia Institute of Technology, Atlanta 30332-0100,
USA.
CONCLUSIONS: Large numbers of molecules can be
delivered intracellularly using low-frequency ultrasound. Both uptake and viability
correlate with acoustic energy, which is useful for design and control of ultrasound
protocols. Transdermal delivery of heparin and
low-molecular weight heparin using low-frequency ultrasound. Mitragotri S,
Kost J. Pharm Res 2001 Aug;18(8):1151-6
Department of
Chemical Engineering, University of California, Santa Barbara 93106, USA
RESULTS:
Low-frequency ultrasound increased permeability of pigskin in vitro and rat skin
in vivo and allowed delivery of biologically active doses of heparin and low-molecular
weight heparin transdermally. A prolonged contact of transdermally delivered heparin
with pigskin was found to reduce the biologic activity of heparin, although no
such deactivation was observed during short exposures. Transdermally delivered
LMWH resulted in sustained aXa levels in the blood. This result was in strong
contrast to subcutaneous or intravenous injections of LMWH, which resulted in
only temporary elevations of aXa level. CONCLUSIONS: Transdermal delivery of low-molecular
weight heparin is a potential alternative to injections. Monomerization
of photosensitizers by ultrasound irradiation in surfactant micellar solutions.
Miyoshi N, Takeshita T, Misik V, Riesz P. Ultrason Sonochem 2001 Oct; 8(4):367-71
Department of Pathology, Fukui Medical University, Matsuoka, Yoshida-gun, Fukui
910-1193, Japan.
CONCLUSIONS: Extrapolation of the experimental
data to in vivo situations suggests that pretreatment of certain photosensitizers
with ultrasound in micellar solutions may lead to increased efficiency of photodynamic
therapy since only the monomers are photodynamically active.
Enhanced protein blotting from PhastGel media to membranes by irradiation of
low-intensity ultrasound. Kost J, Liu LS, Ferreira J, Langer R. Anal Biochem
1994 Jan;216(1):27-32
Department of Chemical Engineering,
Ben-Gurion University, Beer-Sheva, Israel.
A novel approach
to protein blotting based on application of ultrasound is proposed. Three minutes
of ultrasound exposure (1 MHz, 2.5 W/cm2) was sufficient for a very clear transfer
of proteins from a polyacrylamide gel (PhastGel) to nitrocellulose or nylon 66
Biotrans membranes. The proteins evaluated were prestained sodium dodecyl sulfate-polyacrylamide
gel electrophoresis standards (18,500-106,000 Da) and 14C-labeled Rainbow protein
molecular weight markers (14,300-200,000 Da). In control experiments, which were
performed following similar procedures without turning the ultrasonic generator
on, no protein blotting could be seen. For comparable blotting results, 30 min
for electroelution or 240 min for elution by convection blotting was required.
Local delivery of plasmid DNA into rat carotid
artery using ultrasound. Taniyama Y, Tachibana K, Hiraoka K, Namba T Circulation
2002 Mar 12;105(10):1233-9, Yamasaki K, Hashiya N, Aoki M, Ogihara T, Yasufumi
K, Morishita R.
Department of Geriatric Medicine, Osaka
University, Graduate School of Medicine, Osaka, Japan.
CONCLUSIONS:
Overall, we demonstrated that an ultrasound transfection method with Optison enhanced
transfection efficiency of naked plasmid DNA into blood vessels without any apparent
toxicity. Transfection of p53 plasmid with the use of this method should be useful
for safe clinical gene therapy without a viral vector system. Progress
in ultrasonic bioreactors for CELSS applications. Schlager KJ. Adv Space Res
1998;22(10):1453-64
Biotronics Technologies, Inc., Waukesha,
WI 53186, USA.
RESULTS: A series of experimental tests
were carried out with a soybean crop residue meal substrate. Biochemical conversion
rates were significantly expedited with the addition of enzymes and further enhanced
through ultrasonic stimulation of these enzymes. The difference in conversion
rates was particularly increased after the initial period of soluble organics
conversion. The remaining cellulose substrate is much more difficult to biodegrade,
and the ultrasonically-enhanced reaction was able to demonstrate a much higher
rate of substrate conversion. Intracellular drug
delivery using low-frequency ultrasound: quantification of molecular uptake and
cell viability. Keyhani K, Guzman HR, Parsons A, Lewis TN, Prausnitz MR. Pharm
Res 2001 Nov;18(11):1514-20
School of Chemical Engineering,
Georgia Institute of Technology, Atlanta 30332-0100, USA.
CONCLUSIONS:
Large numbers of molecules can be delivered intracellularly using low-frequency
ultrasound. Both uptake and viability correlate with acoustic energy, which is
useful for design and control of ultrasound protocols. In
vitro effects of therapeutic ultrasound on cell proliferation, protein synthesis,
and cytokine production by human fibroblasts, osteoblasts, and monocytes. Doan
N, Reher P, Meghji S, Harris M. J Oral Maxillofac Surg 1999 Apr;57(4):409-19;
discussion 420
Department of Oral and Maxillofacial
Surgery, Eastman Dental Institute/UCL, London, UK.
CONCLUSIONS:
Therapeutic ultrasound induces in vitro cell proliferation, collagen/NCP production,
bone formation, and angiogenesis. These findings support its use in prospective
clinical trials for the prevention and treatment of osteoradionecrosis.
Low-intensity pulsed ultrasound stimulates a bone-forming response in UMR-106
cells. Warden SJ, Favaloro JM, Bennell KL, McMeeken JM, Ng KW, Zajac JD, Wark
JD. Biochem Biophys Res Commun 2001 Aug 24;286(3):443-50
Centre
for Sports Medicine Research and Education, School of Physiotherapy, University
of Melbourne, Melbourne, Victoria, Australia.
RESULTS:
US was found to stimulate expression of the immediate-early response genes c-fos
and COX-2 and elevate mRNA levels for the bone matrix proteins ALP and OC. These
findings suggest that low-intensity pulsed US has a direct effect on bone formation.
This may contribute to the beneficial effect of low-intensity pulsed US on fracture
repair. Frequency dependence of sonophoresis.
Tezel A, Sens A, Tuchscherer J, Mitragotri S. Pharm Res 2001 Dec;18(12):1694-700
Department of Chemical Engineering, University of California
Santa Barbara, California 93106, USA.
RESULTS: The data
showed that for each frequency (in the range of 19.6-93.4 kHz), there exists a
threshold intensity below which no detectable conductivity enhancement was observed.
The threshold intensity increased with frequency. It is feasible to achieve the
desired conductivity (permeability) enhancement regardless of the choice of frequency,
although the necessary energy density is higher at higher frequencies. Low frequencies
(approximately 20 kHz) induced localised transport compared to a more dispersed
effect seen with higher frequencies (approximately 58.9 kHz).
CONCLUSIONS:
This study provides a quantitative understanding of the effects of low-frequency
ultrasound on skin permeability. In vitro study
of low-frequency ultrasound-enhanced transdermal transport of fentanyl and caffeine
across human and hairless rat skin. Boucaud A, Machet L, Arbeille B, Machet
MC, Sournac M, Mavon A, Patat F, Vaillant L. Int J Pharm 2001 Oct 9;228(1-2):69-77
Laboratoire d'Ultrasons Signaux et Instrumentation (EA 2102), School of Medicine,
Tours University, BP 3223, F-37032 Cedex, Tours, France.
The
effect of low-frequency sonophoresis on fentanyl and caffeine permeation through
human and hairless rat skin was studied in vitro. Experiments were performed using
20 kHz ultrasound applied at either continuous or discontinuous mode and with
an average intensity of 2.5 W/cm(2). The results showed that low-frequency ultrasound
enhanced the transdermal transport of both fentanyl and caffeine across human
and hairless rat skin. This was explained by both increasing flux during sonication
and shortening the lag time. Discontinuous mode was found to be more effective
in increasing transdermal penetration of fentanyl while transdermal transport
of caffeine was enhanced by both continuous and pulsed mode. Histological and
electron microscopy studies showed that human and hairless rat skin was unaffected
by ultrasound exposure. Theoretical description
of transdermal transport of hydrophilic permeants: application to low-frequency
sonophoresis. Tang H, Mitragotri S, Blankschtein D, Langer R J Pharm Sci 2001
May;90(5):545-68
Department of Chemical Engineering,
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts
02139, USA.
Application of ultrasound enhances transdermal
transport of drugs (sonophoresis). The enhancement may result from enhanced diffusion
due to ultrasound-induced skin alteration and/or from forced convection. To understand
the relative roles played by these two mechanisms in low-frequency sonophoresis
(LFS, 20 kHz), a theory describing the transdermal transport of hydrophilic permeants
in both the absence and the presence of ultrasound was developed using fundamental
equations of membrane transport, hindered-transport theory, and electrochemistry
principles. Hydrogels with enhanced mass transfer
for transdermal drug delivery. Zhang I, Shung KK, Edwards DA. J Pharm Sci
1996 Dec;85(12):1312-6
Department of Chemical Engineering,
204 Fenske Lab, PA 16802, USA.
The sonophoretic transport
rates of monomeric insulin and vasopressin across human skin in vitro in the presence
of a 20 kHz ultrasound field are shown to differ substantially depending on whether
molecules enter the skin from a saline solution or from a viscous ultrasonic coupling
medium (specifically, a methyl cellulose hydrogel or viscous sol). Theoretically,
the reduction in sonophoretic transport caused by the hydrogels can be explained
by boundary layers that form within the hydrogel owing to the relatively rapid
rate of molecular transport across the (ultrasonically) permeated stratum corneum
as well as poor diffusive mass transfer between the skin and gel. The results
of in vitro experiments performed with an ac current accompanying the ultrasound
show that the mass-transfer barrier posed by the hydrogel can be eliminated for
both vasopressin and insulin by suppressing the diffusive boundary layers, indicating
that relatively high rates of sonophoretic molecular transport across human skin
are achievable when hydrogels are used as the ultrasound coupling medium as long
as method is used to induce molecular mixing within the gel. Difference
in the enhancing effects of ultrasound on the skin permeation of polar and non-polar
drugs. Ueda H, Ogihara M, Sugibayashi K, Morimoto Y. Chem Pharm Bull (Tokyo)
1996 Oct;44(10):1973-6
Faculty of Pharmaceutical Sciences,
Josai University, Saitama, Japan.
The effect of ultrasound
(150 kHz, 111 mW/cm2) on the permeability of isosorbide dinitrate (ISDN) and antipyrine
(ANP) through excised hairless rat skin was evaluated using an Arrhenius plot.
The results suggest that the ultrasound used in the present study increased the
effective diffusivity across the aqueous region in the stratum corneum to enhance
the skin permeation of the polar compound, ANP. Transdermal
drug delivery using low-frequency sonophoresis. Mitragotri S, Blankschtein
D, Langer R. Pharm Res 1996 Mar;13(3):411-20
Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139,
USA.
RESULTS. Application of low-frequency ultrasound
(20 KHz, 125 mW/cm2, 100 msec pulses applied every second) enhanced transdermal
transport of several permeants, including estradiol, salicylic acid, corticosterone,
sucrose, aldosterone, water, and butanol, across human cadaver skin by a factor
in the range of 3 to 3000 and that of salicylic acid across hairless rat skin
in vivo by a factor of up to 300. Low-frequency ultrasound did not induce a long-term
loss of the barrier properties of the skin (in vitro) or damage to living skin
of hairless rats. At a mechanistic level, it is hypothesized that application
of low-frequency ultrasound enhances transdermal transport through aqueous channels
in the SC generated by cavitation-induced bilayer disordering. Support for this
hypothesis is provided using experimental and theoretical analyses of low-frequency
sonophoresis.
CONCLUSIONS. Low-frequency ultrasound
enhances transdermal transport of drugs more effectively than that induced by
therapeutic ultrasound. Transdermal delivery of insulin by ultrasonic vibration.
Tachibana K, Tachibana S. J Pharm Pharmacol 1991 Apr;43(4):270-1 Wakasugi Medical
Research Institute, Fukuoka, Japan. Ultrasonic vibration has been used to deliver
insulin through the skin of hairless mice fasted overnight and partially immersed
in an aqueous solution of insulin (20 units mL-1). The skin surface was exposed
to ultrasonic vibration in two ultrasonic energy ranges (3000-5000 Pa and 5000-8000
Pa) at 48 kHz for 5 min. Blood glucose concentration was measured before and after
exposure to insulin and ultrasonic vibration. In the group subjected to the lower
energy vibrations, blood glucose fell rapidly to reach 34 +/- 11.9% of control
values in 120 min, while when the animals were exposed to higher energy vibrations,
the fall in blood glucose was 22.4 +/- 3.9% of control values at 120 min. The
values remained low for the length of the experiment (240 min). Those exposed
to insulin alone or ultrasonic vibration alone revealed no significant change
in blood glucose concentration. It is postulated that ultrasonic vibration may
alter skin permeability resulting in the absorption of insulin. That the blood
glucose decrease was greater at the higher of the two energy ranges, suggests
this factor could control insulin delivery. Therapeutic
ultrasound: its application in drug delivery. Ng KY, Liu Y. Med Res Rev 2002
Mar;22(2):204-23
Department of Pharmaceutical Sciences,
School of Pharmacy, University of Colorado Health Sciences Center, Campus Box
C-238, 4200 East Ninth Avenue, Denver, Colorado 80262, USA.
Ultrasound is best known for its imaging capability in diagnostic medicine. However,
there have been considerable efforts recently to develop therapeutic uses for
it. The purpose of this review is to summarize some of the recent advances made
in the area of therapeutic ultrasound as they relate to drug delivery. In particular,
this review will focus on the applications of ultrasound to enhance the delivery
and effect of three distinctive therapeutic drug classes: chemotherapeutic, thrombolytic,
and gene-based drugs. In addition, ultrasound contrast agents have been recently
developed for diagnostic ultrasound. New experimental evidence suggests that these
contrast agents can be used as exogenous cavitation nuclei for enhancement of
drug and gene delivery. Thus, brief review of this new class of agents and their
roles in drug delivery will also be provided. By comparison to diagnostic ultrasound,
progress in therapeutic use of ultrasound has been somewhat limited. The recent
successes in ultrasound-related drug delivery research positions ultrasound as
therapeutic tool for drug delivery in the future. Ultrasound
enhances gene expression of liposomal transfection. Unger EC, McCreery TP,
Sweitzer RH. Invest Radiol 1997 Dec;32(12):723-7
ImaRx Pharmaceutical Corporation,
Tucson, Arizona 85719, USA.
RESULTS: Cells survived
30 seconds or less at a power level of 0.5 watts/cm2 but died when exposed for
60 seconds or longer. Exposures of 5 seconds and 30 seconds of ultrasound resulted
in significant increases in gene expression in all three cell types tested in
this experiment.
CONCLUSIONS: Relatively low levels
of ultrasound energy can be used to enhance gene expression from liposomal transfection.
Additional experiments are needed to optimize this process and clarify the mechanisms
involved. The use of sonication for the efficient
delivery of plasmid DNA into cells. Wyber JA, Andrews J, D'Emanuele A. Pharm
Res 1997 Jun;14(6):750-6
School of Pharmacy and Pharmaceutical
Sciences, University of Manchester, UK.
RESULTS: Cell
transformation was optimal at 30 seconds sonication using an output of 2.0 watts
and resulted in a 20 fold enhancement over control values. At extended sonication
times, fewer cells showed evidence of transformation because of reduced cell viability.
The increased DNA uptake and the decreased cell viability were both attributable
to acoustic cavitation events during sonication. The extent of acoustic cavitation
was measured and it was found that there was an increase in cavitation events
with increased sonication time. Cell viability was shown to be directly related
to the number of cavitation events. The effects of sonication on plasmid DNA were
investigated and indicated that the structural integrity of plasmid DNA was unaffected
by the sonication conditions employed.
CONCLUSIONS: Under
controlled conditions, ultrasound is an effective means of delivering plasmid
DNA into cells. The subsequent expression of DNA molecules in cells depends upon
a balance between transient cell damage and cell death.
The use of ultrasound as an enhancer for transcutaneous drug delivery: phonophoresis.
Byl NN. Phys Ther 1995 Jun;75(6):539-53
Graduate Program
in Physical Therapy, School of Medicine, University of California, San Francisco
94122, USA.
Phonophoresis is the use of ultrasound (US)
to enhance the delivery of topically applied drugs. The purposes of this article
are (1) to review the basic principles of transcutaneous drug delivery, (2) to
summarize the functional anatomy of the skin pertinent to phonophoresis, (3) to
outline the physiological principles of US as an enhancer of topically applied
drugs, (4) to review the literature on the efficacy of phonophoresis, (5) to discuss
the relevance of US as an enhancer of topical drugs in the practice of physical
therapy, and (6) to outline areas of needed research. Seventy-five percent of
the studies reviewed reported positive effects of US on local subcutaneous drug
diffusion, but some systemic effects were reported. This research review indicates
that to maximize the clinical effectiveness of phonophoresis: (1) the topical
drug (both the drug and the carrying agent) should transmit US; (2) the skin should
be pretreated with US, heating, moistening, or shaving; (3) the patient needs
to be positioned to maximize circulation during treatment; (4) a dressing that
seals the area and prevents the escape of moisture should be applied after treatment;
(5) an intensity of 1.5 W/cm2 should be used to capture both the thermal and nonthermal
effects of the US; and (6) low-intensity US (0.5 W/cm2) should be used when treating
open wounds or acute injuries. Research is needed to clarify what parameters of
US will most efficiently facilitate topical drug diffusion, how often and for
what duration US should be used to maximize local absorption of drugs, and which
topical drugs can most effectively be used for phonophoresis. Reducing
bacterial resistance to antibiotics with ultrasound. Rediske AM, Rapoport
N, Pitt WG. Lett Appl Microbiol 1999 Jan;28(1):81-4
Brigham
Young University, Provo, UT 84602, USA.
The effect of
erythromycin on planktonic cultures of Psedomonas aeruginosa, with and without
application of 70 kHz ultrasound, was studied. Ultrasound was applied at levels
that had no inhibitory effect on cultures of Ps. aeruginosa. Ultrasound in combination
with erythromycin reduced the viability of Ps. aeruginosa by 1-2 orders of magnitude
compared with antibiotic alone, even at concentrations below the minimum inhibitory
concentration (MIC). Electron-spin resonance studies suggest that ultrasound induces
uptake of antibiotic by perturbing or stressing the membrane. This application
of ultrasound may be useful for expanding the number of drugs available for treating
localized infections by rendering bacteria susceptible to normally ineffective
antibiotics. Ultrasonic enhancement of antibiotic
action on Escherichia coli biofilms: an in vivo model. Rediske AM, Roeder
BL, Brown MK, Nelson JL, Robison RL, Draper DO, Schaalje GB, Robison RA, Pitt
WG. Antimicrob Agents Chemother 1999 May;43(5):1211-4
Department of Microbiology, Brigham Young University, Provo, Utah, USA.
Biofilm infections are a common complication of prosthetic devices in humans.
Previous in vitro research has determined that low-frequency ultrasound combined
with aminoglycoside antibiotics is an effective method of killing biofilms. We
report the development of an in vivo model to determine if ultrasound enhances
antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on
polyethylene disks were implanted subcutaneously on the backs of New Zealand White
female rabbits, one on each side of the spine. Low-frequency (28.48-kHz) and low-power-density
(100- and 300-mW/cm2) continuous ultrasound treatment was applied for 24 h with
and without systemic administration of gentamicin. The disks were then removed,
and the number of viable bacteria on each disk was determined. At the low ultrasonic
power used in this study, exposure to ultrasound only (no gentamicin) caused no
significant difference in bacterial viability. In the presence of antibiotic,
there was a significant reduction due to 300-mW/cm2 ultrasound (P = 0.0485) but
no significant reduction due to 100-mW/cm2 ultrasound. Tissue damage to the skin
was noted at the 300-mW/cm2 treatment level. Further development of this technique
has promise in treatment of clinical implant infections. |
