Mitochondria play a crucial role in the physiological functions and energy metabolism of neurons, which can help in the understanding of complex biochemical reactions associated with various neurodegenerative diseases. Neurons, being highly differentiated terminal cells, require a greater number of mitochondria than ordinary cells to generate significant amounts of ATP, which is necessary for the growth of differentiated neuronal structures like axons and dendrites and the transmission of electrical signals along neuronal axons. Advancements in imaging technology, electrophysiology, and fluorescence targeting labeling have facilitated the study of mitochondrial movements in neurons and axons. However, disordered mitochondrial movements can hinder their analysis and characterization. Thus, it becomes necessary to artificially control their transport. Here, we demonstrate the utilization of scanning optical tweezers (SOTs) on the stable trapping and precise transport of soma or axon of neurons and enable. The presented method provides an optical approach to the control of mitochondria or other organelles in complex and variable biological environment.

Low-cost and biodegradable photothermal wound dressings with remarkable therapeutic effects are highly desirable for next-generation wound healing. Herein, we report an efficient photothermal wound dressing mat made of tellurium nanosheet (TeNS)-loaded electrospun polycaprolactone/gelatin (PCL/GEL) nanofibers. The TeNS-loaded PCL/GEL nanofibrous architectures showed antibacterial efficacy against Escherichia coli and Staphylococcus aureus of 87.68% and 94.57%, respectively. Under near-infrared (NIR) light illumination, they can facilitate cell proliferation as revealed by in vitro scratch assay. The results from in vivo skin wounds combined with tissue staining experiments further showed that the TeNS-loaded dressing could substantially promote wound healing under photothermal conditions. Using immunohistochemical analysis, we found that the TeNS-loaded PCL/GEL nanofibers + NIR group have a high expression of specific antigens in epidermal growth factor (EGF) (P<0.01) and endothelial cell adhesion molecule-31 (CD31, P<0.05), verifying that the nanofibrous mat can stimulate EGF generation and microvessel proliferation. Furthermore, the PCL/GEL/Te+NIR group has the lowest expression in endothelial cell adhesion molecule-68 (CD68, P<0.01), suggesting that the nanofibrous mats have a high anti-inflammatory efficiency. Our work sheds light on the development of novel nonanti-inflammatory wound dressings via photothermal sterilization and the promotion of cell growth using two-dimensional (2D) nanosheets.

Photo-Cross-Linkable hydrogel has attracted immense interest in the regeneration of bone repair and regeneration strategies due to its superior biocompatibility and tunable mechanical properties. Recently, Nb was reported to strongly promote the bone regeneration process via an accelerated osteoblast-modulated alkaline phosphatase activity mechanism. In particular, Nb2C MXenes have drawn widespread attention due to their excellent biocompatibility and ability to induce bone formation. However, the easy agglomeration of Nb2C nanosheets and subsequent low cell endocytosis efficacy greatly suppressed the osteogenesis effect. In this study, a subtractive nanopore-engineered Nb2C MXene was prepared through a microwave combustion method, gelatin methacrylate was used as the carrier hydrogel, and the photo-triggered Porous-Nb2C@GelMA hydrogel was fabricated by a photo-triggered process. The pore-forming strategy not only successfully improved the distribution of Nb2C and formed more homogenous Porous-Nb2C@GelMA hydrogels but also guided bone marrow mesenchymal stem cells (BMSCs) toward osteoblast differentiation. Porous Nb2C provided convenient cellular grasping and endocytosis for BMSCs, which further created a favorable environment for differentiation and osteogenesis. This, in turn, leads to an increase in the expression of osteogenic markers, such as ALP and ARS, as well as osteogenic factors, such as BMP-2, COL-1, OCN, and OPN. Consequently, enhancing the regenerative microenvironment by incorporating porous Nb2C composite hydrogels shows promise for application in bone regeneration.

Programmed cell death (PCD) plays a crucial role in the biological processes of living organisms and occurs in various forms, such as apoptosis, necroptosis and ferroptosis. However, traditional methods for PCD analysis are time-consuming and complex. In this paper, we propose a facile surface-enhanced Raman spectroscopy (SERS)-based strategy for the real-time analysis of three PCD patterns utilizing black phosphorus–gold nanoparticles (BP–Au NPs) as the ultrasensitive unlabeled Raman probe. BP–Au NPs, which possess excellent biocompatibility, are capable of detecting dye molecules at concentrations as low as 5×10−8M and remain stable for at least one week in different physiological environments. In view of this, BP–Au NPs-based SERS technique can distinguish the tiny differences in the molecular fingerprints of cancer cells undergoing three PCD patterns (apoptosis, necroptosis and ferroptosis) triggered by doxorubicin, shikonin and erastin, respectively. We also have real-time monitoring of the intracellular molecular events during PCD, which spy the fluctuations of some typical SERS bands assigned to protein, DNA and lipid, revealing the unique phenotypic characteristics of each PCD pattern. This strategy provides a detailed and comprehensive analysis of the mechanisms of drug-induced PCD at the Raman level.

A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology, laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic problems. The standardized assessment of laser treatment efficacy is crucial for the interpretation and comparison of studies related to laser treatment of skin disorders. In this study, we propose an evaluation method to quantitatively assess laser treatment efficacy based on the image segmentation technology. A tattoo model of Sprague Dawley (SD) rats was established and treated by picosecond laser treatments at varying energy levels. Images of the tattoo models were captured before and after laser treatment, and feature extraction was conducted to quantify the tattooed area and pigment gradation. Subsequently, the clearance rate, which has been a standardized parameter, was calculated. The results indicate that the clearance rates obtained through this quantitative algorithm are comparable and exhibit smaller standard deviations compared with scale scores (4.59% versus 7.93% in the low-energy group, 4.01% versus 9.05% in the medium-energy group, and 4.29% versus 10.23% in the high-energy group). This underscores the greater accuracy, objectivity, and reproducibility in assessing treatment responses. The quantitative evaluation of pigment removal holds promise for facilitating faster and more robust assessments in research and development. Additionally, it may enable the optimization of treatments tailored to individual patients, thereby contributing to more effective and personalized dermatological care.

With advancements in systemic therapy, the incidence of brain metastases (BMs) continues to rise, leading to severe neurological complications. Effective and precise treatment modalities are, therefore, critically important for managing BMs. Radiation therapy (RT), including photon therapy, has been essential in managing BMs. Recent technological advances have significantly enhanced the precision, efficacy, and safety of these treatments. This comprehensive review provides an in-depth examination of the latest advancements in radiation and photon therapy technologies for treating BMs, focusing on innovations such as stereotactic radiosurgery (SRS), whole-brain radiation therapy (WBRT), laser interstitial thermal therapy (LITT), and other radiation-related treatment modalities. Additionally, we discuss clinical outcomes, challenges, and future directions in this rapidly evolving field. While a detailed comparison of techniques is beyond the scope of this paper, this paper provides up-to-date technical information for physicians, medical physicists, patients, and researchers in related fields, potentially enhancing clinical outcomes. Among the treatment modalities, SRS has become a cornerstone of RT for BMs, with its implementation spanning multiple modalities over the past few decades. Given its inherent minimally invasive nature and growing clinical acceptance, SRS is positioned to further evolve as a key therapeutic tool in both neurosurgery and radiotherapy.

Photoacoustic computed tomography (PACT) is an innovative biomedical imaging technique that has gained significant application in the field of biomedicine due to its ability to visualize optical contrast with high resolution and deep tissue penetration. However, the inherent challenges associated with photoacoustic signal excitation, propagation and detection often result in suboptimal image quality. To overcome these limitations, researchers have developed various advanced algorithms that span the entire image reconstruction pipeline. This review paper aims to present a detailed analysis of the latest advancements in PACT algorithms and synthesize these algorithms into a coherent framework. We provide tripartite analysis — from signal processing to reconstruction solution to image processing, covering a spectrum of techniques. The principles and methodologies, as well as their applicability and limitations, are thoroughly discussed. The primary objective of this study is to provide a thorough review of advanced algorithms applicable to PACT, offering both theoretical foundations and practical guidance for enhancing the imaging effect of PACT.

The temperature of an organism provides key insights into its physiological and pathological status. Temperature monitoring can effectively assess potential health issues and plays a critical role in thermal treatment. Photoacoustic imaging (PAI) has enabled multi-scale imaging, from cells to tissues and organs, where its high contrast, deep penetration, and high resolution make it an emerging tool in biomedical imaging field. Benefiting from the linear correlation between the Grüneisen parameter and temperature within the range of 10–55∘C, the PAI has been developed as novel noninvasive label-free tool for temperature monitoring especially for thermotherapy mediated by laser, ultrasound, and microwave. Additionally, by utilizing temperature-responsive photoacoustic nanoprobes, the temperature information of the targeted organism can also be extracted with enhanced imaging contrast and specificity. This review elucidates the basic principles of temperature monitoring technology implemented by PAI, further highlighting the limitations of traditional photoacoustic thermometry, and summarizes recent technological advancements in analog simulation, calibration method, measurement accuracy, nanoprobe design, and wearable improvement. Furthermore, we discuss the biomedical applications of PA temperature monitoring technology in photothermal therapy and ultrasound therapy, finally, anticipating future developments in the field.

Significance: Over 80% of cervical cancer cases occur in lower-to-middle income countries (LMIC’s). This is partly because current screening techniques lack affordability, accessibility, and/or reliability for use in LMIC’s. Aim: To develop an optical technique for cervical cancer screening that is affordable, accessible, and reliable for use in LMIC’s. Approach: We developed a portable diffuse reflectance spectroscopy (DRS) system, which costs <$2500 USD to manufacture, and employs a Raspberry Pi to extract the absorption (μa) and reduced scattering (μs′) coefficients of biological tissue. The system was subject to travel and intentional rough handling. It was further used to capture 320 DRS spectra taken from 64 tissue-mimicking phantoms. Two users collected phantom data, one “expert”, and one “novice” in biomedical optics. The system was also used to collect 335 spectra from colon, small intestine, and rectal tissue of a fresh ex vivo porcine specimen. A previously described artificial intelligence model was used to extract optical properties, and a GradientBoostingClassifier identified the organ of origin for ex vivo spectra. Results: System alignment was robust to intentional rough handling and travel. Phantom μa and μs′ were predicted with average root-mean square error of <10%, regardless of user. Regarding ex vivo data, the system predicted the organ of origin with 80–90% accuracy. Statistical differences between predicted μa were observed in all three organs (p<0.001–0.03), and between μs′ in two organs (p<0.001–0.07). Conclusions: The DRS system has the potential to be affordable, reliable, and accessible for cervical screening in LMIC’s.

Traumatic penumbra (TP) is a region with recoverable potential around the primary lesion of brain injury. Rapid and accurate imaging for identifying TP is essential for treating traumatic brain injury (TBI). In this study, we first established traumatic brain injuries (TBIs) in rats using a modified Feeney method, followed by label-free imaging of brain tissue sections with multiphoton fluorescence microscopy. The results showed that the technique effectively imaged normal and traumatic brain tissues, and revealed pathological features such as extracellular matrix changes, vascular cell proliferation, and intracellular edema in the traumatic penumbra. Compared with normal brain tissue, the extracellular matrix in the TP was sparse, cells were disorganized, and hyperplastic vascular cells emitted higher two-photon excited fluorescence (TPEF) signals. Our research demonstrates the potential of multiphoton fluorescence technology in the rapid diagnosis and therapeutic evaluation of TBI.

Maintaining the s-polarization state of laser beams is important to achieve high modulation depth in a laser-interference-based super-resolution structured illumination microscope (SR-SIM). However, the imperfect optical components can depolarize the laser beams hence degenerating the modulation depth. Here, we first presented a direct measurement method designed to estimate the modulation depth more precisely by shifting illumination patterns with equal phase steps. This measurement method greatly reduces the dependence of modulation depths on the samples, and then developed a polarization optimization method to achieve high modulation depth at all orientations by actively and quantitatively compensating for the additional phase difference using a combination of waveplate and a liquid crystal variable retarder (LCVR). Experimental results demonstrate that our method can achieve illumination patterns with modulation depth higher than 0.94 at three orientations with only one LCVR voltage, which enables isotropic resolution improvement.

Bioluminescent tomography (BLT) is a noninvasive imaging technology that uses optical methods to study physiological and pathological processes at the cellular and molecular levels. It is a powerful tool for early diagnosis and treatment of tumors, as well as drug development. However, the simplified optical transmission models and the ill-posed inverse reconstruction limit its wide applications. The development of deep learning has provided new potential for extending the applications of optical BLT. Researchers have introduced various methods such as neural networks and self-attention mechanisms to improve reconstruction accuracy. Despite these efforts, weak energy points around the reconstructed light source center still impact the accuracy of restoration. In this study, we propose a dual-branch network based on a combination of attention mechanism and fully connected layers (FC-AM) to reduce centroid error and improve reconstruction performance. The network architecture consists of a fully connected (FC) subnetwork and an attention mechanism-based dual-branch (AMDB) subnetwork. The FC subnetwork is used to process input data. AMDB subnetwork is used for deep feature extraction, and captures feature information from different perspectives in parallel. Each branch of the AMDB subnetwork is composed of four AM subnets, which extract features through multilayer linear transformations and attention mechanisms. The outputs of the AMDB are combined through feature fusion to produce the final result. Numerical simulations and experimental results demonstrate that the FC-AM network significantly improves BLT reconstruction performance compared to existing methods (KNN~~LC and AMLC networks), offering enhanced stability and accuracy.