In vivo biocompatibility of three potential intraperitoneal implants

Smart Sensors and Microtechnologies in the Precision Medicine Approach against Lung Cancer

BACKGROUND AND RATIONALE

The therapeutic interventions against lung cancer are currently based on a fully personalized approach to the disease with considerable improvement of patients' outcome. Alongside continuous scientific progresses and research investments, massive technologic efforts, innovative challenges, and consolidated achievements together with research investments are at the bases of the engineering and manufacturing revolution that allows a significant gain in clinical setting.

AIM AND METHODS

The scope of this review is thus to focus, rather than on the biologic traits, on the analysis of the precision sensors and novel generation materials, as semiconductors, which are below the clinical development of personalized diagnosis and treatment. In this perspective, a careful revision and analysis of the state of the art of the literature and experimental knowledge is presented.

RESULTS

Novel materials are being used in the development of personalized diagnosis and treatment for lung cancer. Among them, semiconductors are used to analyze volatile cancer compounds and allow early disease diagnosis. Moreover, they can be used to generate MEMS which have found an application in advanced imaging techniques as well as in drug delivery devices.

CONCLUSIONS

Overall, these issues represent critical issues only partially known and generally underestimated by the clinical community. These novel micro-technology-based biosensing devices, based on the use of molecules at atomic concentrations, are crucial for clinical innovation since they have allowed the recent significant advances in cancer biology deciphering as well as in disease detection and therapy. There is an urgent need to create a stronger dialogue between technologists, basic researchers, and clinicians to address all scientific and manufacturing efforts towards a real improvement in patients' outcome. Here, great attention is focused on their application against lung cancer, from their exploitations in translational research to their application in diagnosis and treatment development, to ensure early diagnosis and better clinical outcomes.

Fabrication and Analysis of Polydimethylsiloxane (PDMS) Microchannels for Biomedical Application

In this research work, Polydimethylsiloxane (PDMS) has been used for the fabrication of microchannels for biomedical application. Under the internet of things (IoT)-based controlled environment, the authors have simulated and fabricated bio-endurable, biocompatible and bioengineered PDMS-based microchannels for varicose veins implantation exclusively to avoid tissue damaging. Five curved ascending curvilinear micro-channel (5CACMC) and five curved descending curvilinear micro-channels (5CDCMC) are simulated by MATLAB (The Math-Works, Natick, MA, USA) and ANSYS (ANSYS, The University of Lahore, Pakistan) with actual environments and confirmed experimentally. The total length of each channel is 1.6 cm. The diameter of both channels is 400 µm. In the ascending channel, the first to fifth curve cycles have the radii of 2.5 mm, 5 mm, 7.5 mm, 10 mm, and 2.5 mm respectively. In the descending channel, the first and second curve cycles have the radii of 12.5 mm and 10 mm respectively. The third to fifth cycles have the radii of 7.5 mm, 5 mm, and 2.5 mm respectively. For 5CACMC, at Reynolds number of 185, the values of the flow rates, velocities and pressure drops are 19.7 µLs−1, 0.105 mm/s and 1.18 Pa for Fuzzy simulation, 19.3 µLs−1, 0.1543 mm/s and 1.6 Pa for ANSYS simulation and 18.23 µLs−1, 0.1332 mm/s and 1.5 Pa in the experiment. For 5CDCMC, at Reynolds number 143, the values of the flow rates, velocities and pressure drops are 15.4 µLs−1, 0.1032 mm/s and 1.15 Pa for Fuzzy simulation, 15.0 µLs−1, 0.120 mm/s and 1.22 Pa for ANSYS simulation and 14.08 µLs−1, 0.105 mm/s and 1.18 Pa in the experiment. Both channels have three inputs and one output. In order to observe Dean Flow, Dean numbers are also calculated. Therefore, both PDMS channels can be implanted in place of varicose veins to have natural blood flow.

Enhancing delivery of small molecule and cell-based therapies for ovarian cancer using advanced delivery strategies

Ovarian cancer is the most lethal gynecological malignancy with a global five-year survival rate of 30-50%. First-line treatment involves cytoreductive surgery and administration of platinum-based small molecules and paclitaxel. These therapies were traditionally administered via intravenous infusion, although intraperitoneal delivery has also been investigated. Initial clinical trials of intraperitoneal administration for ovarian cancer indicated significant improvements in overall survival compared to intravenous delivery, but this result is not consistent across all studies performed. Recently cell-based immunotherapy has been of interest for ovarian cancer. Direct intraperitoneal delivery of cell-based immunotherapies might prompt local immunoregulatory mechanisms to act synergistically with the delivered immunotherapy. Based on this theory, pre-clinical in vivo studies have delivered these cell-based immunotherapies via the intraperitoneal route, with promising results. However, successful intraperitoneal delivery of cell-based immunotherapy and clinical adoption of this technique will depend on overcoming challenges of intraperitoneal delivery and finding the optimal combinations of dose, therapeutic and delivery route. We review the potential advantages and disadvantages of intraperitoneal delivery of cell-based immunotherapy for ovarian cancer and the pre-clinical and clinical work performed so far. Potential advanced delivery strategies, which might improve the efficacy and adoption of intraperitoneal delivery of therapy for ovarian cancer, are also outlined.

Decellularized extracellular matrix bioinks and the external stimuli to enhance cardiac tissue development in vitro

Engineered heart tissue (EHT) has ample potential as a model for in vitro tissue modeling or tissue regeneration. Using 3D cell printing technology, various hydrogels have been utilized as bioinks to fabricate EHT to date. However, its efficacy has remained limited due to poor functional properties of the cultured cardiomyocytes stemming from a lack of proper microenvironmental cues. Specifically, the surrounding matrix plays a key role in modulating cardiomyocyte differentiation and maturation. Recently, the use of heart tissue-derived extracellular matrix (hdECM) bioink has come to be seen as one of the most promising candidates due to its functional and structural similarities to native tissue. Here, we demonstrated a correlation between the synthesis of cardiomyocyte-specific proteins and the surrounding microenvironment irrespective of the similar material chemistry. Primary cardiomyocytes isolated from neonatal rats were encapsulated in different composition and concentration of bioinks (hdECM and collagen). The bioinks were sequentially printed using an extrusion-based 3D bioprinter and cultured either statically or dynamically. Qualitative and quantitative evaluation revealed enhanced maturation of cardiomyocytes in hdECM, unlike the collagen group under similar culture conditions. Specifically, 3D-printed EHT using a low concentration of hdECM promoted early differentiation of cardiomyocytes. Hence, the present study provides experimental insights regarding the establishment of a 3D-printed cardiac tissue model, highlighting that the matrix and the culture microenvironment can be decisive factors for cell-material interactions that affect cardiomyocyte maturation. STATEMENT OF SIGNIFICANCE: The regulation of signal transduction and responses to extracellular matrices (ECMs) is of particular relevance in tissue maturation. In particular, there is a clear need to understand the structural and phenotypical modulation in cardiomyocytes with respect to the surrounding microenvironment. Exploration of the key regulators, such as the compositional and the biophysical properties of bioinks associated directly with cell-cell and cell-matrix interactions would assist with the fabrication of cardiac tissue constructs with enhanced functionality. Hence, we documented the synergistic effects of surrounding matrices and culture conditions on the maturation of cardiomyocytes. Additionally, we highlighted the potential of using 3D bioprinting techniques to fabricate uniformly aligned cardiac constructs for mid- to high-throughput drug testing platforms that have great reproducibility and versatility.

In vivo wireless photonic photodynamic therapy

An emerging class of targeted therapy relies on light as a spatially and temporally precise stimulus. Photodynamic therapy (PDT) is a clinical example in which optical illumination selectively activates light-sensitive drugs, termed photosensitizers, destroying malignant cells without the side effects associated with systemic treatments such as chemotherapy. Effective clinical application of PDT and other light-based therapies, however, is hindered by challenges in light delivery across biological tissue, which is optically opaque. To target deep regions, current clinical PDT uses optical fibers, but their incompatibility with chronic implantation allows only a single dose of light to be delivered per surgery. Here we report a wireless photonic approach to PDT using a miniaturized (30 mg, 15 mm³) implantable device and wireless powering system for light delivery. We demonstrate the therapeutic efficacy of this approach by activating photosensitizers (chlorin e6) through thick (>3 cm) tissues inaccessible by direct illumination, and by delivering multiple controlled doses of light to suppress tumor growth in vivo in animal cancer models. This versatility in light delivery overcomes key clinical limitations in PDT, and may afford further opportunities for light-based therapies.

Microscale Bioreactors for in situ characterization of GI epithelial cell physiology

The development of in vitro artificial small intestines that realistically mimic in vivo systems will enable vast improvement of our understanding of the human gut and its impact on human health. Synthetic in vitro models can control specific parameters, including (but not limited to) cell types, fluid flow, nutrient profiles and gaseous exchange. They are also “open” systems, enabling access to chemical and physiological information. In this work, we demonstrate the importance of gut surface topography and fluid flow dynamics which are shown to impact epithelial cell growth, proliferation and intestinal cell function. We have constructed a small intestinal bioreactor using 3-D printing and polymeric scaffolds that mimic the 3-D topography of the intestine and its fluid flow. Our results indicate that TEER measurements, which are typically high in static 2-D Transwell apparatuses, is lower in the presence of liquid sheer and 3-D topography compared to a flat scaffold and static conditions. There was also increased cell proliferation and discovered localized regions of elevated apoptosis, specifically at the tips of the villi, where there is highest sheer. Similarly, glucose was actively transported (as opposed to passive) and at higher rates under flow.

Influence of the PDMS substrate stiffness on the adhesion of Acanthamoeba castellanii

BACKGROUND

Mechanosensing of cells, particularly the cellular response to substrates with different elastic properties, has been discovered in recent years, but almost exclusively in mammalian cells. Much less attention has been paid to mechanosensing in other cell systems, such as in eukaryotic human pathogens.

RESULTS

We report here on the influence of substrate stiffness on the adhesion of the human pathogen Acanthamoebae castellanii (A. castellanii). By comparing the cell adhesion area of A. castellanii trophozoites on polydimethylsiloxane (PDMS) substrates with different Young's moduli (4 kPa, 29 kPa, and 128 kPa), we find significant differences in cell adhesion area as a function of substrate stiffness. In particular, the cell adhesion area of A. castellanii increases with a decreasing Young's modulus of the substrate.

CONCLUSION

The dependence of A. castellanii adhesion on the elastic properties of the substrate is the first study suggesting a mechanosensory effect for a eukaryotic human pathogen. Interestingly, the main targets of A. castellanii infections in the human body are the eye and the brain, i.e., very soft environments. Thus, our study provides first hints towards the relevance of mechanical aspects for the pathogenicity of eukaryotic parasites.

Attachment of alginate microcapsules onto plasma-treated PDMS sheet for retrieval after transplantation

Although transplantation of microencapsulated islets has been proposed as a therapy for the treatment of diabetes mellitus, limited retrievability of the cells has impeded its medical usage. To achieve retrieval of microencapsulated islets, capsules were attached to polydimethylsiloxane (PDMS) with a biocompatible adhesive. Because the hydrophobic nature of the PDMS surface prevents attachment, surface modification is essential. Alginate microcapsules were attached to modified PDMS sheets, and the mechanical stability of the resulting constructs was determined. Acrylic acid (AA) and acrylamide (AM) mixtures were grafted on the surfaces of PDMS sheets using a two-step oxygen plasma treatment (TSPT). TSPT-PDMS was characterized according to water contact angle and zeta-potential measurements. The contact angle was altered by changing the ratio of AM to AA to generate hydrophilic surface. Evaluation of the surface charge at pH 2, 7, and 12 confirmed the presence of polar groups on the modified surface. Microcapsules were attached to TSPT-PDMS using Histoacryl® and shown to be in a monolayered and half-exposed state. The shear stress resistance of alginate capsules attached to the PDMS sheet indicates the possibility of transplantation of encapsulated cells without scattering in vivo. This method is applicable to retrieve microencapsulated porcine islets when required.

Photoinitiated chemical vapor deposition of cytocompatible poly(2-hydroxyethyl methacrylate) films

Poly(2-hydroxyethyl methacrylate) (pHEMA) is a widely utilized biomaterial due to lack of toxicity and suitable mechanical properties; conformal thin pHEMA films produced via chemical vapor deposition (CVD) would thus have broad biomedical applications. Thin films of pHEMA were deposited using photoinitiated CVD (piCVD). Incorporation of ethylene glycol diacrylate (EGDA) into the pHEMA polymer film as a crosslinker, confirmed via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, resulted in varied swelling and degradation behavior. 2-Hydroxyethyl methacrylate-only films showed significant thickness loss (up to 40%), possibly due to extraction of low-molecular-weight species or erosion, after 24 h in aqueous solution, whereas films crosslinked with EGDA (9.25-12.4%) were stable for up to 21 days. These results differ significantly from those obtained with plasma-polymerized pHEMA, which degraded steadily over a 21-day period, even with crosslinking. This suggests that the piCVD films differ structurally from those fabricated via plasma polymerization (plasma-enhanced CVD). piCVD pHEMA coatings proved to be good cell culture materials, with Caco-2 cell attachment and viability comparable to results obtained on tissue-culture polystyrene. Thus, thin film CVD pHEMA offers the advantage of enabling conformal coating of a cell culture substrate with tunable properties depending on method of preparation and incorporation of crosslinking agents.