Rigidity (or stiffness) of materials and extracellular matrix has proven to be one of the most significant extracellular physicochemical cues that can control diverse cell behaviors, such as contractility, motility, and spreading, and the resultant pathophysiological phenomena. Many 2D materials engineered with tunable rigidity have enabled researchers to elucidate the roles of matrix biophysical cues in diverse cellular events, including migration, lineage specification, and mechanical memory. Moreover, the recent findings accumulated under 3D environments with viscoelastic and remodeling properties pointed to the importance of dynamically changing rigidity in cell fate control, tissue repair, and disease progression. Thus, here we aim to highlight the works related with material/matrix-rigidity-mediated cell and tissue behaviors, with a brief outlook into the studies on the effects of material/matrix rigidity on cell behaviors in 2D systems, further discussion of the events and considerations in tissue-mimicking 3D conditions, and then examination of the in vivo findings that concern material/matrix rigidity. The current discussion will help understand the material/matrix-rigidity-mediated biological phenomena and further leverage the concepts to find therapeutic targets and to design implantable materials for the treatment of damaged and diseased tissues.

Regenerative endodontic treatment based on tissue engineering has recently gained interest in contemporary restorative dentistry. However, low survival rates and poor potential differentiation of stem cells could undermine the success rate of pulp regenerative therapy. Human gingival fibroblast-conditioned medium (hGF-CM) has been considered a potential therapy for tissue regeneration due to its stability in maintaining multiple factors essential for tissue regeneration compared to live cell transplantation. This study aimed to investigate the potency of hGF-CM on stem cells from human dental pulp (DPSC) in pulp regeneration. A series of experiments confirmed that hGF-CM contributes to a significant increase in proliferation, migration capability, and cell viability of DPSC after H₂O₂ exposure. Moreover, it has been proved to facilitate the odontogenic differentiation of DPSC via qRT-PCR, ALP (alkaline phosphatase), and ARS (Alizarin Red S) staining. It has been discovered that such highly upregulated odontogenesis is related to certain types of ECM proteins (collagen and laminin) from hGF-CM via proteomics. In addition, it is found that the ERK pathway is a key mechanism via inhibition assay based on RNA-seq result. These findings demonstrate that hGF-CM could be beneficial biomolecules for pulp regeneration.

Sb-doped SiO_1.2/SiO₂ and InP-doped Si/SiO₂ multilayers were prepared on p-type Si (100) wafers by ion beam sputtering and were subsequently annealed to form n-type Si quantum dots (QDs)/ptype crystalline Si heterojunction solar cells. Maximum energy-conversion efficiencies of 4.73 and 6.06% were obtained from the Sb- and the P-doped Si-QD solar cells, respectively. Based on the photovoltaic (PV) parameters, including the open-circuit voltage, short-circuit current density, fill factor, and energy-conversion efficiency, and on the photoluminescence (PL) spectra, we discuss possible physical mechanisms to explain the close correlation between the PV and the PL characteristics. These results are very promising for the development of next-generation all-Si-QD solar cells.

This study compared the solubility, water absorption, dimensional stability, release of various ions (hydroxyl, calcium, sulfur, strontium, and silicon), and cytotoxicity of lightcured resin-modified pulp-capping materials. Resin-modified calcium hydroxide (Ultrablend™ plus, UBP), light-cured resin-modified calcium silicate (TheraCal LC™, TLC), and dual-cure resin-modified calcium silicate (TheraCal PT™, TPT) were used. Each material was polymerized; solubility, 24-hour water absorption, and 30- day dimensional stability experiments were conducted to test its physical properties. Solubility was assessed according to the ISO 6876 standard, and 24 hours of water absorption, 30 days of dimensional stability were assessed by referring to the previous protocol respectively. Eluates at 3 and 24 hours and on 7, 14, and 28 days were analyzed according to the ISO 10993-12 standard. And the pH, Ion-releasing ability, cell proliferation rate, and cell viability were assessed using the eluates to evaluate biochemical characteristics. pH was measured with a pH meter and Ion-releasing ability was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Cell proliferation rate and cell viability were assessed using human dental pulp cells (hDPCs). The former was assessed by an absorbance assay using the CCK-8 solution, and the latter was assessed by Live and Dead staining. TPT exhibited lower solubility and water absorption than TLC. UBP and TPT demonstrated higher stability than TLC. The release of sulfur, strontium, calcium, and hydroxyl ions was higher for TLC and TPT than for UBP. The 28-day release of hydroxyl and silicon ions was similar for TLC and TPT. TLC alone exhibited a lower cell proliferation rate compared to the control group at a dilution ratio of 1 : 2 in cell proliferation and dead cells from Live and Dead assay evaluation. Thus, when using light-cure resin-modified pulp-capping materials, calcium silicate-based materials can be considered alternatives to calcium hydroxide-based materials. Moreover, when comparing physical and biochemical properties, TPT could be prioritized over TLC as the first choice.

Mechanical forces are central determinants of development, homeostasis, and pathology in oral and maxillofacial tissues, yet most regenerative strategies continue to prioritize biochemical signaling over mechanical control. In anatomically and functionally heterogenous tissues such as dentin-pulp, periodontium, temporomandibular joint, oral mucosa, and salivary glands, mechanics is not a secondary cue but a primary regulator of cell fate, immune responses, and tissue integration. This review reframes oral and maxillofacial regeneration through a mechanobiological engineering lens, summarizing how region-specific mechanical loading is sensed and transduced through focal adhesions, mechanosensitive ion channels, cytoskeletal tension, and nuclear mechanotransduction to coordinate tissue-specific repair programs. We organize recent advances into two complementary strategies. Intrinsic mechanobiological design exploits biomaterial stiffness, hierarchical topography, anisotropic and modular architectures, and piezoelectric functionality to recreate tissue-appropriate mechanical niches. Extrinsic mechanotherapy leverages engineered in vitro platforms and clinically adaptable physical modalities including vibration, low-intensity ultrasound, electrical stimulation, and magnetic fields - to activate endogenous regenerative pathways. We further discuss critical barriers to clinical translation, including the lack of physiologically realistic testbeds, insufficient standardization of mechanical dose, fatigue and durability under cyclic loading, and challenges in scalable manufacturing. Finally, we highlight emerging opportunities in adaptive biomaterials coupled with multiscale modeling and AI-assisted, data-driven design to integrate mechanical, biological, and functional outcome data. By positioning mechanics as a design and dosing variable rather than a passive property, this review provides a framework for developing reproducible, clinically relevant therapies that restore both biological function and mechanical performance in oral and maxillofacial tissues.