Programming cancer through phase-functionalized silicon based biomaterials

Dual-Purpose 3D-Silica Nanostructure Matrix for Rapid Epigenetic Reprogramming of Tumor Cell to Cancer Stem Cell Spheroid

Cancer stem cells (CSCs), a rare subpopulation responsible for tumorigenesis and therapeutic resistance, are difficult to characterize and isolate. Conventional method of growing CSCs takes up to 2-8 weeks inhibiting the rate of research. Therefore, rapid reprogramming (RR) of tumor cells into CSCs is crucial to accelerate the stem cell oncology research. The current RR techniques cannot be utilized for CSC RR due to many limitations posed due to isolation requirements resulting in loss of vital data. Hence, a technique that can induce CSC RR without the need for isolation procedures is needed. Here, fabrication of a 3D-silica nanostructured extracellular matrix for RR and in situ monitoring is reported. The RR is tested using three preclinical cancer models. The 3D matrix and a zeta potential study confirm an intense material-cellular interaction resulting in the enhanced expressions of surface and epigenetic biomarkers. Cancer cells require only 3-day period to form CSC spheroids with 3D-silica extracellular matrix. Real-time single-cell monitoring of the methylene blue-induced photodynamic demonstrates the dual functionality. To the authors' knowledge, this is the first study to demonstrate a CSC epigenetic reprogramming using nanostructures. These findings may pave the path for accelerating the stem cell research in oncology.

Regulating MDA-MB-231 breast cancer cell adhesion on laser-patterned surfaces with micro- and nanotopography

Breast cancer is the most common type of cancer observed in women. Communication with the tumor microenvironment allows invading breast cancer cells, such as triple negative breast cancer cells, to adapt to specific substrates. The substrate topography modulates the cellular behavior among other factors. Several different materials and micro/nanofabrication techniques have been employed to develop substrates for cell culture. Silicon-based substrates present a lot of advantages as they are amenable to a wide range of processing techniques and they permit rigorous control over the surface structure. We investigate and compare the response of the triple negative breast cancer cells (MDA-MB-231) on laser-patterned silicon substrates with two different topographical scales, i.e., the micro- and the nanoscale, in the absence of any other biochemical modification. We develop silicon surfaces with distinct morphological characteristics by employing two laser systems with different pulse durations (nanosecond and femtosecond) and different processing environments (vacuum, SF₆ gas, and water). Our findings demonstrate that surfaces with microtopography are repellent, while those with nanotopography are attractive for MDA-MB-231 cell adherence.

Functionalized Stress Component onto Bio-template as a Pathway of Cytocompatibility

This in-vitro study introduces residual stress as a third dimension of cell stimulus to modulate the interaction between cells and bio-template, without the addition of either chemical or physical stimuli onto the bio-template surface. Ultrashort Pulsed Laser (USPL) irradiation of silicon-based bio-template causes recrystallization of silicon, which mismatches the original crystal orientation of the virgin silicon. Consequently, subsurface Induced Residual Stress (IRS) is generated. The IRS components demonstrated a strong cytocompatibility, whereas the peripheral of IRS, which is the interface between the IRS component and the virgin silicon surface, a significant directional cell alignment was observed. Fibroblast cells shown to be more sensitive to the stress component than Hela cancer cells. It revealed that cytocompatibility in terms of cell migration and directional cell alignment is directly proportional to the level of the IRS component. Higher stress level results in more cell alignment and border migration width. There is a stress threshold below which the stress component completely loses the functionality. These results pointed to a functionalized bio-template with tunable cytocompatibility. This study may lead to a new tool for the designing and engineering of bio-template.

Noble Hybrid Nanostructures as Efficient Anti-Proliferative Platforms for Human Breast Cancer Cell

Nanomaterials have proven to possess great potential in biomaterials research. Recently, they have suggested considerable promise in cancer diagnosis and therapy. Among others, silicon (Si) nanomaterials have been extensively employed for various biomedical applications; however, the utilization of Si for cancer therapy has been limited to nanoparticles, and its potential as anticancer substrates has not been fully explored. Noble nanoparticles have also received considerable attention owing to unique anticancer properties to improve the efficiency of biomaterials for numerous biological applications. Nevertheless, immobilization and control over delivery of the nanoparticles have been challenge. Here, we develop hybrid nanoplatforms to efficiently hamper breast cancer cell adhesion and proliferation. Platforms are synthesized by femtosecond laser processing of Si into multiphase nanostructures, followed by sputter-coating with gold (Au)/gold-palladium (Au-Pd) nanoparticles. The performance of the developed platforms was then examined by exploring the response of normal fibroblast and metastatic breast cancer cells. Our results from the quantitative and qualitative analyses show a dramatic decrease in the number of breast cancer cells on the hybrid platform compared to untreated substrates. Whereas, fibroblast cells form stable adhesion with stretched and elongated cytoskeleton and actin filaments. The hybrid platforms perform as dual-acting cytophobic/cytostatic stages where Si nanostructures depress breast cancer cell adhesion while immobilized Au/Au-Pd nanoparticles are gradually released to affect any surviving cell on the nanostructures. The nanoparticles are believed to be taken up by breast cancer cells via endocytosis, which subsequently alter the cell nucleus and may cause cell death. The findings suggest that the density of nanostructures and concentration of coated nanoparticles play critical roles on cytophobic/cytostatic properties of the platforms on human breast cancer cells while having no or even cytophilic effects on fibroblast cells. Because of the remarkable contrary responses of normal and cancer cells to the proposed platform, we envision that it will provide novel applications in cancer research.