4D hydrogels: fabrication strategies, stimulation mechanisms, and biomedical applications.

Shape-morphing hydrogels have emerged as a promising biomaterial due to their ability to mimic the anisotropic tissue composition by creating a gradient in local swelling behavior. In this case, shape deformations occur due to the non-uniform distribution of internal stresses, asymmetrical swelling, and shrinking of different parts of the same hydrogel. Herein, we discuss the four-dimensional (4D) fabrication techniques (extrusion-based printing, dynamic light processing, and solvent casting) employed to prepare shape-shifting hydrogels. The important distinction between mono- and dual-component hydrogel systems, the capabilities of 3D constructs to undergo uni- and bi-directional shape changes, and the advantages of composite hydrogels compared to their pristine counterparts are presented. Subsequently, various types of actuators such as moisture, light, temperature, pH, and magnetic field and their role in achieving the desired and pre-determined shapes are discussed. These 4D gels have shown remarkable potential as programmable scaffolds for tissue regeneration and drug-delivery systems. Finally, we present futuristic insights into integrating piezoelectric biopolymers and sensors to harvest mechanical energy from motions during shape transformations to develop self-powered biodevices.

DNA interactive property of poly-L-lysine induces apoptosis in MCF-7 cells through DNA interaction.

Poly-L-lysine (PLL) is known to be an encapsulating agent in drug formulation and delivery. PLL also has apoptotic and antiproliferative activities that enable blocking of the tumorigenesis process. However, the dose-selective activities of PLL in exerting apoptosis against cancer are unclear. Therefore, this study has been designed to explore the potential role and dose of PLL in apoptosis, if any. For this, PLL was administered at several doses in cancer cell lines and was found to be more potent against MCF-7 cells. PLL causes mitochondria-mediated apoptotic death through the upregulation of cleaved caspase-3. To investigate the mechanism responsible for this activity, we have analyzed if PLL could have the DNA interactive property or not. For this, molecular docking analysis was carried out to prove whether it has the property to bind with DNA or not. Studies have revealed that PLL is a potent DNA binder and it probably performs such apoptotic activities through the binding of cellular DNA early in an exposure. Simultaneous upregulation of both ROS-mediated stress and also in key protein expressions like Î³-H2AX could also help us to confirm that PLL induces apoptosis through DNA interaction. This finding leads us to believe that PLL could play an interfering role with other chemotherapeutic compounds when used as a drug-coating material as it exerts an apoptotic effect on cancer cells, which should be avoided by using a much lower concentration.

Poly-l-Lysine inhibits VEGF and c-Myc mediated tumor-angiogenesis and induces apoptosis in 2D and 3D tumor microenvironment of both MDA-MB-231 and B16F10 induced mice model.

Cancer is a widespread disease that has shown promising mortality worldwide. Our previous study has been shown the efficacy of Poly-l-lysine (PLL) as a promising cytotoxic effect against cancer cells. However, exact-mechanism of PLL in 3D physiological relevant tumor-microenvironment and against tumor-angiogenesis has never been analysed. In this study, we have investigated apoptotic efficacy of PLL, if any in opposition to proliferative aggressive cancer cell MDA-MB-231 both 2D and-3D cell culture conditions. Furthermore, PLL was administered in B16F10 murine melanoma cells induced BALB/c mice model. The study has been designed through transcription and translation level of PLL-induced tumor-angiogenesis and apoptotic gene-expression modulation level and various relevant histological studies in comparison with untreated control. Studies have shown anti-proliferative and anti-tumor angiogenic efficacy of PLL better in in-vitro 3D tumor-microenvironment against MDA-MB-231 breast cancer cells. Furthermore, in-vivo model, PLL was found to suppress tumorigenesis process at minimum dose. PLL found to induce apoptosis through-upregulation of cytosolic-cytochrome-C, caspase-3 and PARP activations when administered in B16F10 induced in-vivo tumor. In blocking proliferation and tumor-angiogenesis, PLL was found to be effective as it significantly downregulated activity of VEGF, VEGFR2, Ki-67 and c-Myc expression. As PLL blocked tumor progression and induced DNA-break, also upregulated apoptotic process and recovered tissue architecture as revealed from histological study in comparison with untreated control. Overall PLL was found to be a promising anti-tumor angiogenic and anti-proliferative drug that was effective both in in-vitro breast cancer 3D tumor-microenvironment and in-vivo metastatic-mice-model.

In-vitro and in-vivo evaluation of polymeric microsphere formulation for colon targeted delivery of 5-fluorouracil using biocompatible natural gum katira.

The aim was to develop oral site-specific rate-controlled anticancer drug delivery to pacify systemic side-effects and offer effective and safe therapy for colon cancer with compressed dose and duration of treatment. The double emulsion solvent evaporation method was employed. To check functionality, DAPI-staining and in-vivo anticancer study of Ehrlich Ascites Carcinoma bearing mice was tested. Histopathology of liver and kidney and Cell morphology of EAC cell was also performed. Formulated and optimized polymeric microsphere of 5-FU showed excellent physicochemical features. In-vitro, DAPI results pointed drug-treated groups displayed the prominent feature of apoptosis. The percentage of apoptotic of entrapped drug played in a dose-dependent manner. Significant decreases in EAC liquid tumors and increased life span of treated mice were observed. Rate of variation of cell morphology was more in 5-FU loaded microsphere than 5-FU injection. Hematological and biochemical parameter's and Histopathology of liver and kidney resulted that due to control released formulation have slow release rate, that gives less trace on liver and kidney function. Finally, we foresee that polymeric microsphere of 5-FU applying natural gum katira could be an assuring micro-carrier for active colon targeting delivery tool with augmented chemotherapeutic efficacy and lowering side effect against colon cancer.

Induction of apoptosis, anti-proliferation, tumor-angiogenic suppression and down-regulation of Dalton's Ascitic Lymphoma (DAL) induced tumorigenesis by poly-l-lysine: A mechanistic study.

PURPOSE: The present study, attempts to validate the molecular mechanism(s) of Poly-l-lysine (PLL) induced apoptosis, anti-proliferative and anti-tumorigenic properties in in-vitro HUVECs cells and Dalton's Ascitic Lymphoma (DAL) and in in-vivo DAL cell bearing BALB/c mice model. MATERIALS AND METHODS: The cell proliferation assay and morphological assay was carried out using the MTT assay and Giemsa staining method. The antitumor activity of PLL was evaluated in BALB/c mice at 20 and 40 mg/kg/b.w doses for 21 days for DAL solid tumor model. Several tumor evaluation endpoints, hematological and biochemical parameters were estimated. Additionally, the tumor apoptosis, anti-proliferative and anti-tumor angiogenesis effects were assessed using western blots and immunohistochemistry. RESULTS: PLL significantly decreased cell proliferation in in-vitro HUVECs and DAL cells without significant effects on normal cell growth. PLL also induced alteration in cellular morphology in DAL cells. Therafter, in the BALB/c mouse model, PLL had noticeable inhibition in DAL-induced tumorigenesis. This inhibition was evident through reduced solid tumor volume and weight versus the control group. However, PLL promoted tumor apoptosis and suppressed cell-proliferation and tumor-angiogenesis. PLL also increased hematological markers significantly compared to 5-flurouracil (5-FU). The amount of TdT in the nuclei of DAL cells in mice treated with PLL was significantly increased while in contrast decreases of anti-apoptotic protein Bcl-2 expression were observed. PLL also significantly upregulated the pro-apoptotic protein Bax and activated caspase-3. Measurable decreases of cyclin-D1 were observed through PLL treatments, an indicator of cell-cycle arrest. These studies also indicate PLL's induction and anti-proliferative effects through suppression of the c-Myc and Ki-67 proliferation-indices. Additionally, PLL inhibited tumor-angiogenesis through suppression of VEGF and CD34 protein expression levels and reduction ofmicrovesseldensityversus similar parameters in tumors from control mice. CONCLUSION: The present study offers opportunities and hopes for possible anti-tumortherapies with PLL in the near future and warrants further formulation developments.

Poly-L-Lysine Inhibits Tumor Angiogenesis and Induces Apoptosis in Ehrlich Ascites Carcinoma and in Sarcoma S-180 Tumor

Background: This study focuses on the role of Poly-L-lysine (PLL), an essential amino acid, on molecular changes of tumor angiogenesis suppression, pro-apoptotic and anti-apoptotic gene expression after treatment on Ehrlich ascites carcinoma (EAC) and solid sarcoma-180 tumor cells bearing mice. Materials and Methods: The cell viability was carried out using MTT assay. The antitumor activity was evaluated by treatment with PLL at 20 and 40mg/kg/b.w doses for 14 days in EAC ascites tumor and 21 days for Sarcoma-180 solid tumor model. Several tumor evaluation studies, haematological and biochemical parameters were estimated. Importantly, the tumor cell apoptosis was assessed using microscopic observations, DNA fragmentation assay, Flow cytometric analysis, cell-cycle and electron-microscopic study, following which, the expression of several signal proteins related to pro-apoptosis, anti-apoptosis and tumor angiogenesis were quantified using western blotting and immunohistochemistry study. Results: Precisely, PLL had cytotoxic effect on K562; A549; U937 and B16F10 cancer cells. Significant decreases in liquid and solid tumors and increased life span of treated mice were observed (P<0.05). Typical morphological changes, apoptosis bleb phenomenon and sub-G1 cell cycle arrests revealed that PLL promoted apoptotic cell death. Western blot and immunohistochemistry confirms, PLL activated apoptotic signalling cascades through down regulation of Bcl-2 and CD31 protein and upregulation of Bax and p53 proteins. The anti-angiogenic effects were also accompanied with decreased VEGF expression and reduced peritoneal-angiogenesis and microvessel density. Conclusions: The antitumor and antitumor-angiogenic activity of PLL was confirmed from all the results via up and down regulation of relevant signal proteins reported in this publication.