The modulation of myogenic cells differentiation using a semiconductor-muscle junction

Cellular Activity Modulation Mediated by Near Infrared-Irradiated Polydopamine Nanoparticles: In Vitro and Ex Vivo Investigation

The precise control of cell activity is crucial for understanding and potentially treating many disorders. Focusing on neurons and myotubes, recent advancements in nanotechnology have introduced photoresponsive nanoparticles as an alternative tool for modulating cell function with high spatial and temporal resolution. This approach offers a noninvasive alternative to traditional stimulation techniques, reducing potential tissue damage and improving the specificity of cell activation. Here, we introduce an approach envisioning fully organic polydopamine nanoparticles (PDNPs) to remotely modulate the activity of differentiated SH-SY5Y cells and differentiated C2C12 cells, via near-infrared (NIR) laser stimulation. Confocal microscopy imaging revealed the possibility of thermally activating individual neuron-like cells, eliciting a significant cellular response characterized by the generation of calcium transients and the subsequent release of the neurotransmitter acetylcholine. Similarly, we demonstrated the possibility of precisely triggering the muscle contraction of single myotubes. Additionally, we investigated the antioxidant properties of PDNPs, demonstrating their capacity to prevent an increase in oxidative stress levels related to an increase in intracellular temperature. Moreover, proteomic analysis revealed that a PDNP treatment could positively affect neuronal plasticity and nervous system maturation, besides promoting muscle growth and preserving its functional integrity, underscoring its potential to support both neural and musculoskeletal development. Eventually, the effect of the NIR laser irradiation in the presence of PDNPs in neuron-like cells was successfully evaluated ex vivo on brains of Drosophila melanogaster, genetically modified to express the fluorescent calcium indicator jGCaMP7c.

Gold Nanoshell-Mediated Remote Myotube Activation

Mild heat stimulation of muscle cells within the physiological range represents an intriguing approach for the modulation of their functions. In this work, photothermal conversion was exploited to remotely stimulate striated muscle cells by using gold nanoshells (NSs) in combination with near-infrared (NIR) radiation. Temperature increments of approximately 5 °C were recorded by using an intracellular fluorescent molecular thermometer and were demonstrated to efficiently induce myotube contraction. The mechanism at the base of this phenomenon was thoroughly investigated and was observed to be a Ca²⁺-independent event directly involving actin-myosin interactions. Finally, chronic remote photothermal stimulations significantly increased the mRNA transcription of genes encoding heat shock proteins and sirtuin 1, a protein which in turn can induce mitochondrial biogenesis. Overall, we provide evidence that remote NIR + NS muscle excitation represents an effective wireless stimulation technique with great potential in the fields of muscle tissue engineering, regenerative medicine, and bionics.

Graphite Oxide to Graphene. Biomaterials to Bionics

The advent of implantable biomaterials has revolutionized medical treatment, allowing the development of the fields of tissue engineering and medical bionic devices (e.g., cochlea implants to restore hearing, vagus nerve stimulators to control Parkinson's disease, and cardiac pace makers). Similarly, future materials developments are likely to continue to drive development in treatment of disease and disability, or even enhancing human potential. The material requirements for implantable devices are stringent. In all cases they must be nontoxic and provide appropriate mechanical integrity for the application at hand. In the case of scaffolds for tissue regeneration, biodegradability in an appropriate time frame may be required, and for medical bionics electronic conductivity is essential. The emergence of graphene and graphene-family composites has resulted in materials and structures highly relevant to the expansion of the biomaterials inventory available for implantable medical devices. The rich chemistries available are able to ensure properties uncovered in the nanodomain are conveyed into the world of macroscopic devices. Here, the inherent properties of graphene, along with how graphene or structures containing it interface with living cells and the effect of electrical stimulation on nerves and cells, are reviewed.

Overview of micro- and nano-technology tools for stem cell applications: micropatterned and microelectronic devices

In the past few decades the scientific community has been recognizing the paramount role of the cell microenvironment in determining cell behavior. In parallel, the study of human stem cells for their potential therapeutic applications has been progressing constantly. The use of advanced technologies, enabling one to mimic the in vivo stem cell microenviroment and to study stem cell physiology and physio-pathology, in settings that better predict human cell biology, is becoming the object of much research effort. In this review we will detail the most relevant and recent advances in the field of biosensors and micro- and nano-technologies in general, highlighting advantages and disadvantages. Particular attention will be devoted to those applications employing stem cells as a sensing element.