Characterization and in vitro bioactivity evaluation of polyvinyl alcohol incorporated electro spun chitosan/ fluor apatite nanofibrous scaffold for bone tissue engineering.

In this study, polyvinyl alcohol/chitosan/fluor apatite scaffolds with different concentrations of polyvinyl alcohol of 0.075 g ml-1 and 0.1 g ml-1, respectively named A and B fabricated by electrospinning method to use in tissue engineering. By examining the scaffolds by FE-SEM, an appetite layer formation which was on the scaffold surface was clearly observable. Increasing the concentration of polyvinyl alcohol from 0.075 g ml-1 to 0.1 g ml-1 in the nanofibrous scaffolds improved degradation characteristic with an optimized value of 26 ± 2 and 42 ± 1 % after 28 days, respectively. The mean diameter of fibers both scaffolds was 405 nm and 212 nm, respectively. Furthermore, the percentage of porosity in both scaffolds was calculated as 84% and 91%, separately. The level of hydrophilicity of the scaffolds was measured by the dynamic contact angle method. Moreover, the increase in the percentage of polyvinyl alcohol led to the decrease in the average contact angle in scaffold A and scaffold B from 90° to 70°, respectively. The results of bone marrow culture test with MG-63 (NCBI C555) cell on the surface of scaffolds demonstrated not cytotoxicity in the resulting scaffolds as well as a suitable substrate for the adhesion and growth of the cells. According to our findings, the electrospun fluorapatite-incorporated-chitosan/polyvinyl alcohol scaffold could provide a new nanocomposite for biomedical applications.

Laser thrombolysis and in vitro release kinetics of tPA encapsulated in chitosan polysulfate-coated nanoliposome.

A major challenge in managing coronary artery disease is to find an effective thrombolytic therapy with minimal side effects. Laser thrombolysis is a practical procedure to remove the thrombus from inside blocked arteries, although it can cause embolism and re-occlusion of the vessel. The present study aimed to design a liposome drug delivery system for the controlled release of tissue plasminogen activator (tPA) and delivery of drug system into the thrombus by Nd:YAG laser at a wavelength of 532 nm for the treatment of arterial occlusive diseases. In this study, tPA encapsulated into the chitosan polysulfate-coated liposome (Lip/PSCS-tPA) was fabricated by a thin-film hydration technique. The particle size of Lip/tPA and Lip/PSCS-tPA was 88 and 100 nm, respectively. The release rate of tPA from Lip/PSCS-tPA was measured to be 35 % and 66 % after 24 h and 72 h, respectively. Thrombolysis through the delivery of Lip/PSCS-tPA into the thrombus during the laser irradiation was higher compared to irradiated thrombus without the nanoliposomes. The expression of IL-10 and TNF-α genes was studied by RT-PCR. The level of TNF-α for Lip/PSCS-tPA was lower than that of tPA, which can lead to improved cardiac function. Also, in this study, the thrombus dissolution process was studied using a rat model. After 4 h, the thrombus area in the femoral vein was significantly lower for groups treated with Lip/PSCS-tPA (5 %) compared to the groups treated with tPA alone (45 %). Thus, according to our results, the combination of Lip/PSCS-tPA and laser thrombolysis can be introduced as an appropriate technique for accelerating thrombolysis.

Controlled release of protein from gelatin/chitosan hydrogel containing platelet-rich fibrin encapsulated in chitosan nanoparticles for accelerated wound healing in an animal model.

The physiological healing process is disrupted in many cases using the current wound healing procedures, resulting in delayed wound healing. Hydrogel wound dressings provide a moist environment to enhance granulation tissue and epithelium formation in the wound area. However, exudate accumulation, bacterial proliferation, and reduced levels of growth factors are difficulties of hydrogel dressings. Here, we loaded platelet-rich fibrin-chitosan (CH-PRF) nanoparticles into the gelatin-chitosan hydrogel (Gel-CH/CH-PRF) by solvent mixing method. Our goal was to evaluate the characteristics of hydrogel dressings, sustained release of proteins from the hydrogel dressing containing PRF, and reduction in the risk of infection by the bacteria in the wound area. The Gel-CH/CH-PRF hydrogel showed excellent swelling behavior, good porosity, proper specific surface area, high absorption of wound exudates, and proper vapor permeability rate (2023 g/m 2.day), which provided requisite moisture without dehydration around the wound area. Thermal behavior and the protein release from the hydrogels were investigated using simultaneous thermal analysis and the Bradford test, respectively. Most importantly, an excellent ability to control the release of proteins from the hydrogel dressings was observed. The high antimicrobial activity of hydrogel was confirmed using Gram-positive and Gram-negative bacteria. Due to the presence of chitosan in the hydrogels, the lowest scavenging capacity-50 value (5.82 µgmL-1) and the highest DPPH radical scavenging activity (83 %) at a concentration 25 µgmL-1 for Gel-CH/CH-PRF hydrogel were observed. Also, the hydrogels revealed excellent cell viability and proliferation. The wound healing process was studied using an in vivo model of the full-thickness wound. The wound closure was significantly higher on Gel-CH/CH-PRF hydrogel compared to the control group, indicating the highest epidermis thickness, and enhancing the formation of new granulation tissue. Our findings demonstrated that Gel-CH/CH-PRF hydrogel can provide an ideal wound dressing for accelerated wound healing.

Engineering organ-on-a-chip systems to model viral infections.

Infectious diseases remain a public healthcare concern worldwide. Amidst the pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 infection, increasing resources have been diverted to investigate therapeutics targeting the COVID-19 spike glycoprotein and to develop various classes of vaccines. Most of the current investigations employ two-dimensional (2D) cell culture and animal models. However, 2D culture negates the multicellular interactions and three-dimensional (3D) microenvironment, and animal models cannot mimic human physiology because of interspecies differences. On the other hand, organ-on-a-chip (OoC) devices introduce a game-changer to model viral infections in human tissues, facilitating high-throughput screening of antiviral therapeutics. In this context, this review provides an overview of thein vitroOoC-based modeling of viral infection, highlighting the strengths and challenges for the future.

Advances and challenges in developing smart, multifunctional microneedles for biomedical applications.

Microneedles (MNs) have been developed as minimally invasive tools for diagnostic and therapeutic applications. However, in recent years, there has been an increasing interest in developing smart multifunctional MN devices to provide automated and closed-loop systems for body fluid extraction, biosensing, and drug delivery in a stimuli-responsive manner. Although this technology is still in its infancy and far from being translated into the clinic, preclinical trials have shown some promise for the broad applications of multifunctional MN devices. The main challenge facing the fabrication of smart MN patches is the integration of multiple modules, such as drug carriers, highly sensitive biosensors, and data analyzers in one miniaturized MN device. Researchers have shown the feasibility of creating smart MNs by integrating stimuli-responsive biomaterials and advanced microscale technologies, such as microsensors and microfluidic systems, to precisely control the transportation of biofluids and drugs throughout the system. These multifunctional MN devices can be envisioned in two distinct strategies. The first type includes individual drug delivery and biosensing MN units with a microfluidic system and a digital analyzer responsible for fluid transportation and communication between these two modules. The second type relies on smart biomaterials that can function as drug deliverers and biosensors by releasing drugs in a stimuli-responsive manner. These smart biomaterials can undergo structural changes when exposed to external stimuli, such as pH and ionic changes, mimicking the biological systems. Studies have demonstrated a high potential of hydrogel-based MN devices for a wide variety of biomedical applications, such as drug and cell delivery, as well as interstitial fluid extraction. Biodegradable hydrogels have also been advantageous for fabricating multifunctional MNs due to their high loading capacity and biocompatibility with the drug of choice. Here, we first review a set of MN devices that can be employed either for biosensing or delivery of multiple target molecules and compare them to the conventional and more simple systems, which are mainly designed for single-molecule sensing or delivery. Subsequently, we expand our insight into advanced MN systems with multiple competencies, such as body fluid extraction, biosensing, and drug delivery at the point of care. The improvement of biomaterials knowledge and biofabrication techniques will allow us to efficiently tune the next generation of smart MNs and provide a realistic platform for more effective personalized therapeutics.

Droplet-based microfluidics in biomedical applications.

Droplet-based microfluidic systems have been employed to manipulate discrete fluid volumes with immiscible phases. Creating the fluid droplets at microscale has led to a paradigm shift in mixing, sorting, encapsulation, sensing, and designing high throughput devices for biomedical applications. Droplet microfluidics has opened many opportunities in microparticle synthesis, molecular detection, diagnostics, drug delivery, and cell biology. In the present review, we first introduce standard methods for droplet generation (i.e. passive and active methods) and discuss the latest examples of emulsification and particle synthesis approaches enabled by microfluidic platforms. Then, the applications of droplet-based microfluidics in different biomedical applications are detailed. Finally, a general overview of the latest trends along with the perspectives and future potentials in the field are provided.

Recent developments in mussel-inspired materials for biomedical applications.

Over the decades, researchers have strived to synthesize and modify nature-inspired biomaterials, with the primary aim to address the challenges of designing functional biomaterials for regenerative medicine and tissue engineering. Among these challenges, biocompatibility and cellular interactions have been extensively investigated. Some of the most desirable characteristics for biomaterials in these applications are the loading of bioactive molecules, strong adhesion to moist areas, improvement of cellular adhesion, and self-healing properties. Mussel-inspired biomaterials have received growing interest mainly due to the changes in mechanical and biological functions of the scaffold due to catechol modification. Here, we summarize the chemical and biological principles and the latest advancements in production, as well as the use of mussel-inspired biomaterials. Our main focus is the polydopamine coating, the conjugation of catechol with other polymers, and the biomedical applications that polydopamine moieties are used for, such as matrices for drug delivery, tissue regeneration, and hemostatic control. We also present a critical conclusion and an inspired view on the prospects for the development and application of mussel-inspired materials.

Platelet-rich fibrin-loaded PCL/chitosan core-shell fibers scaffold for enhanced osteogenic differentiation of mesenchymal stem cells.

Here, we fabricated the platelet-rich fibrin (PRF)-loaded PCL/chitosan (PCL/CS-PRF) core-shell nanofibrous scaffold through a coaxial electrospinning method. Our goal was to evaluate the effect of CS-RPF in the core layer of the nanofibrous on the osteogenic differentiation of human mesenchymal stem cells (HMSCs). The elastic modulus of PCL/CS-PRF core-shell scaffold (44 MPa) was about 1.5-fold of PCL/CS scaffold (25 MPa). The specific surface area of the scaffolds increased from 9.98 m2/g for PCL/CS scaffold to 16.66 m2/g for the PCL/CS-PRF core-shell nanofibrous scaffold. Moreover, the release rate of PRF from PCL/CS-PRF nanofibrous scaffold was measured to be 24.50% after 10 days which showed slow and sustained release of PRF from the nanofibrous. The formation of Ca-P on the surface of scaffold immersed in simulated body fluid solution indicated the suitable osteoconductivity of PCL/CS-PRF core-shell nanofibrous scaffold. Also, the value of ALP activity and calcium deposited on the surface of PCL/CS-PRF core-shell nanofibrous scaffold were 81.97 U/L and 40.33 µg/scaffold, respectively after 14 days, which confirmed the significantly higher amounts of ALP and calcium deposition on the scaffold containing PRF compared to PCL/CS scaffold. Due to higher hydrophilicity and porosity of PCL/CS-PRF core-shell nanofibrous scaffold compared to PCL/CS scaffold, a better bone cell growth on surface of PCL/CS-PRF scaffold was observed. The Alizarin red-positive area was significantly higher on PCL/CS-PRF scaffold compared to PCL/CS scaffold, indicating more calcium deposition and osteogenic differentiation of HMSCs in the presence of PRF. Our findings demonstrate that PCL/CS-PRF core-shell scaffolds can provide a strong construct with improved osteogenic for bone tissue engineering applications.

Micro and Nanoscale Technologies for Diagnosis of Viral Infections.

Viral infection is one of the leading causes of mortality worldwide. The growth of globalization significantly increases the risk of virus spreading, making it a global threat to future public health. In particular, the ongoing coronavirus disease 2019 (COVID-19) pandemic outbreak emphasizes the importance of devices and methods for rapid, sensitive, and cost-effective diagnosis of viral infections in the early stages by which their quick and global spread can be controlled. Micro and nanoscale technologies have attracted tremendous attention in recent years for a variety of medical and biological applications, especially in developing diagnostic platforms for rapid and accurate detection of viral diseases. This review addresses advances of microneedles, microchip-based integrated platforms, and nano- and microparticles for sampling, sample processing, enrichment, amplification, and detection of viral particles and antigens related to the diagnosis of viral diseases. Additionally, methods for the fabrication of microchip-based devices and commercially used devices are described. Finally, challenges and prospects on the development of micro and nanotechnologies for the early diagnosis of viral diseases are highlighted.

Multimaterial bioprinting and combination of processing techniques towards the fabrication of biomimetic tissues and organs.

Tissue reconstruction requires the utilization of multiple biomaterials and cell types to replicate the delicate and complex structure of native tissues. Various three-dimensional (3D) bioprinting techniques have been developed to fabricate customized tissue structures; however, there are still significant challenges, such as vascularization, mechanical stability of printed constructs, and fabrication of gradient structures to be addressed for the creation of biomimetic and complex tissue constructs. One approach to address these challenges is to develop multimaterial 3D bioprinting techniques that can integrate various types of biomaterials and bioprinting capabilities towards the fabrication of more complex structures. Notable examples include multi-nozzle, coaxial, and microfluidics-assisted multimaterial 3D bioprinting techniques. More advanced multimaterial 3D printing techniques are emerging, and new areas in this niche technology are rapidly evolving. In this review, we briefly introduce the basics of individual 3D bioprinting techniques and then discuss the multimaterial 3D printing techniques that can be developed based on combination of these techniques for the engineering of complex and biomimetic tissue constructs. We also discuss the perspectives and future directions to develop state-of-the-art multimaterial 3D bioprinting techniques for engineering tissues and organs.

Role of biomaterials in the diagnosis, prevention, treatment, and study of corona virus disease 2019 (COVID-19).

Recently emerged novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting corona virus disease 2019 (COVID-19) led to urgent search for methods to prevent and treat COVID-19. Among important disciplines that were mobilized is the biomaterials science and engineering. Biomaterials offer a range of possibilities to develop disease models, protective, diagnostic, therapeutic, monitoring measures, and vaccines. Among the most important contributions made so far from this field are tissue engineering, organoids, and organ-on-a-chip systems, which have been the important frontiers in developing tissue models for viral infection studies. Also, due to low bioavailability and limited circulation time of conventional antiviral drugs, controlled and targeted drug delivery could be applied alternatively. Fortunately, at the time of writing this paper, we have two successful vaccines and new at-home detection platforms. In this paper, we aim to review recent advances of biomaterial-based platforms for protection, diagnosis, vaccination, therapeutics, and monitoring of SARS-CoV-2 and discuss challenges and possible future research directions in this field.

Healthy and diseased in vitro models of vascular systems.

Irregular hemodynamics affects the progression of various vascular diseases, such atherosclerosis or aneurysms. Despite the extensive hemodynamics studies on animal models, the inter-species differences between humans and animals hamper the translation of such findings. Recent advances in vascular tissue engineering and the suitability of in vitro models for interim analysis have increased the use of in vitro human vascular tissue models. Although the effect of flow on endothelial cell (EC) pathophysiology and EC-flow interactions have been vastly studied in two-dimensional systems, they cannot be used to understand the effect of other micro- and macro-environmental parameters associated with vessel wall diseases. To generate an ideal in vitro model of the vascular system, essential criteria should be included: 1) the presence of smooth muscle cells or perivascular cells underneath an EC monolayer, 2) an elastic mechanical response of tissue to pulsatile flow pressure, 3) flow conditions that accurately mimic the hemodynamics of diseases, and 4) geometrical features required for pathophysiological flow. In this paper, we review currently available in vitro models that include flow dynamics and discuss studies that have tried to address the criteria mentioned above. Finally, we critically review in vitro fluidic models of atherosclerosis, aneurysm, and thrombosis.

Phytogenic Synthesis of Nickel Oxide Nanoparticles (NiO) Using Fresh Leaves Extract of Rhamnus triquetra (Wall.) and Investigation of Its Multiple In Vitro Biological Potentials.

Chemically nickel oxide nanoparticles (NiONPs) involve the synthesis of toxic products, which restrict their biological applications. Hence, we developed a simple, eco-friendly, and cost-efficient green chemistry method for the fabrication of NiONPs using fresh leaf broth of Rhamnus triquetra (RT). The RT leaves broth was used as a strong reducing, capping, and stabilizing agent in the formation of RT-NiONPs. The color change in solution from brown to greenish black suggests the fabrication of RT-NiONPs which was further confirmed by absorption band at 333 nm. The synthesis and different physicochemical properties of RT-NiONPs were investigated using different analytical techniques such as UV-Vis (ultraviolet-visible spectroscopy), XRD (X-ray powder diffraction), FT-IR (Fourier-transform infrared spectroscopy), SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy-dispersive X-ray spectroscopy), DLS (dynamic light scattering) and Raman. Further, RT-NiONPs were subjected to different in vitro biological activities and revealed distinctive biosafe and biocompatibility potentials using erythrocytes and macrophages. RT-NiONPs exhibited potential anticancer activity against liver cancer cell lines HUH7 (IC50: 11.3 µg/mL) and HepG2 (IC50: 20.73 µg/mL). Cytotoxicity potential was confirmed using Leishmanial parasites promastigotes (IC50: 27.32 µg/mL) and amastigotes (IC50: 37.4 µg/mL). RT-NiONPs are capable of rendering significant antimicrobial efficacy using various bacterial and fungal strains. NiONPs determined potent radical scavenging and moderate enzyme inhibition potencies. Overall, this study suggested that RT-NiONPs can be an attractive and eco-friendly candidate. In conclusion, current study showed potential in vitro biological activities and further necessitate different in vivo studies in various animal models to develop leads for new drugs to treat several chronic diseases.

Electroactive graphene oxide-incorporated collagen assisting vascularization for cardiac tissue engineering.

The application of a cardiac patch over the epicardial surface has shown positive effects in protecting cardiac function postinfarction. Electroactive patches could enhance electrical signal propagation among cardiac cells. In the present study, an electrically active composite of collagen and graphene oxide (Col-GO) was fabricated as a cardiac patch. Col scaffolds were fabricated using a freeze-drying method and coated covalently with GO. Some scaffolds were also reduced by a reduction agent to restore the high conductivity of GO. GO was shown to be a single layer with suitable lateral size for biological application. The Col-GO scaffolds contained randomly oriented interconnected pores with appropriate pore sizes of 120-138 ± 8 µm. GO flakes were also well distributed in the pore walls. By increasing the GO concentration, the tensile strength of the scaffolds was enhanced from 75 kPa for Col-GO-5 to 162 kPa for Col-GO-90. Young modulus also followed the same trend. Electrical conductivity of the scaffolds was in the range of semi-conductive materials (~10-4 S/m), which is suitable for cardiac tissue engineering applications. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated no toxic effects on human umbilical vein endothelial cells (HUVECs) after 96 h. Also, a 10-days degradation product of the samples was compatible with HUVECs. Reduced scaffolds supported neonatal cardiomyocyte adhesion and upregulated the expression of the cardiac genes, including Cx43, Actin4, and Trpt-2 than their nonconductive counterparts. The obtained results confirmed the angiogenic properties of reduced Go-containing materials for cardiovascular applications where angiogenesis plays an important role, especially postinfarction. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 204-219, 2019.

In vitro evaluation of collagen immobilization on polytetrafluoroethylene through NH3 plasma treatment to enhance endothelial cell adhesion and growth.

BACKGROUND: Polytetrafluoroethylene (PTFE) is poorly biocompatible due to its low surface energy and hydrophobicity, which cause weak cell attachment and proliferation and complicate its use in implants. OBJECTIVE: NH3 plasma was used for surface modification and binding of amine groups on the PTFE surface. Collagen was immobilized on the plasma-treated PTFE in order to enable it to support enhanced cell adhesion and growth. METHODS: PTFE was exposed to NH3 plasma and collagen was immobilized on the NH3 plasma-treated surface. ATR-IR, SEM, EDXA and contact angle were conducted to determine the composition, microstructure and wettability of samples. The cytocompatibility of the samples was assessed via the growth HUVEC cells using MTT assay. RESULTS: Plasma treatment resulted in an incorporation of functional groups, containing N2 and O2 that caused the PTFE surface to become hydrophilic with contact angle 68°. Also, a reduction in F/C ratio was observed after collagen immobilization that indicates the presence of collagen. Cells proliferated in greater numbers on the collagen immobilized-PTFE as compared to the plasma-treated one. CONCLUSIONS: Plasma treatment incorporates functional polar moieties on the PTFE surface, causing enhanced wettability, collagen immobilization and cell viability. Collagen-immobilized PTFE may offer a valuable solution in biomedical applications such as vessel grafts.

Enhanced Entrapment and Improved in Vitro Controlled Release of N-Acetyl Cysteine in Hybrid PLGA/Lecithin Nanoparticles Prepared Using a Nanoprecipitation/Self-Assembly Method.

To enhance the in vitro controlled release of N-acetyl cysteine (NAC), hybrid nanoparticles (NPs) consisting of a poly(lactide-co-glycolide) (PLGA) hydrophobic core and a soybean lecithin mono-layer coat were prepared. Hybrid NPs were synthesized using a nanoprecipitation combined with self-assembly method. To characterize prepared NPs, zeta potential, diameter size, surface morphology, disparity, and lipid coating of hybrid NPs were detrmined using dynamic light scattering, scanning electron microscope and Fourier transform infrared spectroscopy techniques. High-performance liquid chromatography was employed to evaluate drug loading yield and encapsulation efficiency and in vitro drug release of prepared NPs. The cytotoxicity of hybrid NPs was assayed on normal L929 alveolar epithelial cells using MTT method. Prepared NPs were found to disperse as individual NPs with a well-defined spherical shape. The hydrodynamic diameter and surface charge of NAC-loaded hybrid NPs were 81.8 ± 1.3 nm and -33.1 ± 2.1 mV, respectively. Drug loading yield and encapsulation efficiency of NAC-loaded hybrid NPs were found to be 38 ± 2.1% and 67 ± 5.7%, respectively. Prepared hybrid NPs showed no significant cytotoxicity against normal alveolar cells. Our data suggest that the hybrid PLGA-lecithin NPs may be An efficient controlled release drug delivery system for NAC. J. Cell. Biochem. 118: 4203-4209, 2017. © 2017 Wiley Periodicals, Inc.

Characterization of a novel nanobiomaterial fabricated from HA, TiO2 and Al2O3 powders: an in vitro study.

For the purposes of this study, hydroxyapatite (HA)-Al2O3-TiO2 nanobiomaterial with significant surface properties and biocompatibility capable of forming surface apatite was fabricated by cold-press and sintering method. Samples were examined for hardness and porosity. The results showed that in terms of hardness and porosity, sample A (50 wt% TiO2-30 wt% HA-20 wt% Al2O3) was superior to sample B (30 wt% TiO2-50 wt% HA-20 wt% Al2O3), and also the density of nanobiomaterial was close to natural bone density. Bioactivity of the samples in a simulated body fluid (SBF) was investigated. Then, after immersing the samples in SBF solution for a period of 7 days, sample B exhibited greater ability to form calcium phosphate compounds on the surface as compared to sample A. In addition, in vitro studies showed that MG-67 osteoblast-like cells attached and spread on the samples surface. The results showed that cells proliferated in greater numbers on the sample B as compared to the sample A. Finally, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis were performed to identify phases, study microstructure, and determine percentage of elements, respectively. The results revealed that considering their different properties, both nanobiomaterials can be used in medical applications.

Dynamic study of PLGA/CS nanoparticles delivery containing drug model into phantom tissue using CO2 laser for clinical applications.

In this study, cationic nanoparticles (NPs) were prepared by coating chitosan (CS) on the surface of PLGA NPs. To our knowledge most of the work in the field of drug delivery systems using lasers has been performed using short pulses with micron and submicron durations. We carried out an experiment using superlong PLS-R (10 ms) and CW CO2 laser modes on simulated drug-biogelatin model where drug was encapsulated by PLGA/CS NPs. Maximum depth of drug containing cavitation was achieved faster at higher powers and shorter irradiation time in CWC mode. We believe that the main mechanism at work with superlong pulses is both photothermal due to vaporization and photomechanical due to photophoresis and cavitation collapse. In the case of CW, however, it is purely photothermal. Thus, drug molecules can be transported into tissue bulk by thermal waves which can be described by the Fick's law in 3-D model for a given cavity geometry and the mechanical waves, unlike only by pure photomechanical waves (i.e. photoacoustically) as with short pulses. Therefore, our studies could offer an alternative for currently existing method for drug delivery.