Minimal Tissue Research Articles

Intravascular delivery of an ultraflexible neural electrode array for recordings of cortical spiking activity

Although intracranial neural electrodes have significantly contributed to both fundamental research and clinical treatment of neurological diseases, their implantation requires invasive surgery to open craniotomies, which can introduce brain damage and disrupt normal brain functions. Recent emergence of endovascular neural devices offers minimally invasive approaches for neural recording and stimulation. However, existing endovascular neural devices are unable to resolve single-unit activity in large animal models or human patients, impeding a broader application as neural interfaces in clinical practice. Here, we present the ultraflexible implantable neural electrode as an intravascular device (uFINE-I) for recording brain activity at single-unit resolution. We successfully implanted uFINE-Is into the sheep occipital lobe by penetrating through the confluence of sinuses and recorded both local field potentials (LFPs) and multi-channel single-unit spiking activity under spontaneous and visually evoked conditions. Imaging and histological analysis revealed minimal tissue damage and immune response. The uFINE-I provides a practical solution for achieving high-resolution neural recording with minimal invasiveness and can be readily transferred to clinical settings for future neural interface applications such as brain-machine interfaces (BMIs) and the treatment of neurological diseases.

Microfabrication Technologies for Nanoinvasive and High-Resolution Magnetic Neuromodulation.

The increasing demand for precise neuromodulation necessitates advancements in techniques to achieve higher spatial resolution. Magnetic stimulation, offering low signal attenuation and minimal tissue damage, plays a significant role in neuromodulation. Conventional transcranial magnetic stimulation (TMS), though noninvasive, lacks the spatial resolution and neuron selectivity required for spatially precise neuromodulation. To address these limitations, the next generation of magnetic neurostimulation technologies aims to achieve submillimeter-resolution and selective neuromodulation with high temporal resolution. Invasive and nanoinvasive magnetic neurostimulation are two next-generation approaches: invasive methods use implantable microcoils, while nanoinvasive methods use magnetic nanoparticles (MNPs) to achieve high spatial and temporal resolution of magnetic neuromodulation. This review will introduce the working principles, technical details, coil designs, and potential future developments of these approaches from an engineering perspective. Furthermore, the review will discuss state-of-the-art microfabrication in depth due to its irreplaceable role in realizing next-generation magnetic neuromodulation. In addition to reviewing magnetic neuromodulation, this review will cover through-silicon vias (TSV), surface micromachining, photolithography, direct writing, and other fabrication technologies, supported by case studies, providing a framework for the integration of magnetic neuromodulation and microelectronics technologies.

Effectiveness and biocompatibility of a novel Schlemm’s canal microstent for glaucoma management

To evaluate the effectiveness and biocompatibility of Wistend, a novel Schlemm’s canal (SC) microstent made of Nitinol designed to improve aqueous humor outflow. New Zealand white (NZW) rabbits were divided into blank, sham-operated and Wistend groups. ICare® Tonovet Plus®, swept-source optical coherence tomography (SS-OCT), slit lamp biomicroscopy, retinal camera and scanning electron microscopy (SEM) were used for preoperative and postoperative observations. Hematoxylin and Eosin (H&E) tissue staining was adopted for biocompatibility. A significant difference in intraocular pressure (IOP) between the Wistend group and the control groups was observed during the six-month follow-up. SS-OCT identified arc line internal reflections within the SC in the anterior chamber angle. Conjunctival congestion and edema gradually diminished in the early stages. No corneal vascularization, no anterior chamber inflammatory response and no significant tissue reactions were noted in any groups. SEM showed the Wistend’s windows and orifices remained clear, encircled by minimal incidental ocular tissue and free from blockage. Histopathological examination revealed no discernible differences between the Wistend-implanted and sham-operated eyes. These in vivo studies demonstrate the effectiveness and biocompatibility of the microstent. Our findings suggest a promising potential for Wistend in significantly reducing IOP and effectively facilitating the outflow of aqueous humor.

Exploring the Potential of Tunnel Field-Effect Transistors in Biomedical Devices: A Comprehensive Survey

Implantable medical devices have revolutionized healthcare by providing continuous monitoring and therapeutic interventions within the human body. The overall performance of these devices is heavily dependent on the effectiveness and efficiency of integrated electronic components, such as transistors. This survey explores the growing utilization of Tunnel Field-Effect Transistors (TFETs) in implantable devices, shedding light on their advantages and challenges in this specific application domain. TFETs, characterized by their unique tunnelling mechanism, offer several advantages that make them well suited for implantable devices. Their low-power consumption, reduced leakage current, and improved subthreshold swing make them ideal for energy-efficient, long-lasting operation within the constrained power budgets of implantable devices. Furthermore, TFETs exhibit excellent performance at low supply voltages, ensuring minimal tissue damage and heat generation. This survey also addresses the challenges associated with TFETs in implantable devices, including fabrication complexities, variability, and compatibility with existing technologies. It highlights recent advancements in TFET technology that address these concerns, such as improved material choices and manufacturing techniques. As technology continues to advance, TFETs are poised to play a pivotal role in improving the overall efficiency and reliability of life-saving technologies and medical devices. Overall, this survey provides valuable insights into the current state and future prospects of TFETs in implantable devices, guiding researchers and engineers in harnessing their potential for the benefit of healthcare and patient well-being.

ROS1 Translocation Detection in NSCLC: A Comparative Study of PGDx and FISH

Abstract In the United States, lung cancer is the leading cause of cancer-related deaths. In recent decades, the advent of molecularly-targeted therapies in the management of non-small-cell lung cancer (NSCLC) has led to significant improvements in patient outcomes. As such, optimum care depends on timely molecular testing. The mutational spectrum associated with NSCLC, however, is complex and riddled with various point mutations, amplifications, and rearrangements/fusions across multiple genes. Comprehensive testing of NSCLC has historically required multiple testing modalities to detect all clinically-relevant molecular targets. At our institution, a combination of immunohistochemistry, fluorescence in situ hybridization (FISH), and sequencing-based tests are performed on all NSCLCs. Though fragmented, this approach ensures testing for all current targetable genetic alterations is performed. Unfortunately, this style of testing is often incompatible with the limited amount of tumor tissue acquired by biopsy. In 2021, our institution implemented PGDx elio tissue complete (PGDx), introducing redundancy in ROS1 translocation testing, previously assessed by FISH through send-out testing to Mayo Clinic. The objective of this study was to perform a retrospective analysis of our molecular testing experience for NSCLC, with a spotlight on the nuances of ROS1 testing. Since its implementation at our institution, PGDx has been performed on 172 cases of NSCLC. As part of our NSCLC reflex testing agreement, ROS1 translocation FISH testing was also attempted on all cases. Of the 172 cases, one clinically actionable ROS1 translocation was identified by PGDx (0.5%). Interestingly, FISH testing for this case was equivocal. The remaining cases were negative for ROS1 translocations. Notably, FISH failed in six cases (3.5%) due to insufficient tissue. Three additional cases (1.7%) had minimal tumor tissue available for FISH testing (less than 300 cells), providing suboptimal results. Altogether, PGDx was successfully performed on all samples and, in the 166 cases where FISH was successful, there was no discordance between orthogonal tests. This supports the validity and reliability of PGDx in identifying clinically relevant rearrangements/fusions in ROS1. In this study, we demonstrate that PGDx can effectively replace FISH testing for ROS1 translocations in NSCLC. In addition to being technically equivalent to FISH for ROS1 with comparable turnaround times, PGDx adds substantial benefits. Replacing FISH testing with PGDx improves the diagnostic workflow, improves tissue utilization, and eliminates the costs associated with send-out orders. The cost of Mayo ROS1 FISH testing averages $520 per sample and this amount is billed to patient insurance, though reimbursements vary. Further, PGDx can detect the ROS1 gene fusion partners, a feature not possible through routine FISH testing in NSCLC. This added clinical information reduces the ambiguity of equivocal FISH results, exemplified by our study. By implementing this change, our institution will optimize both diagnostic practices and resource utilization in the clinical setting.

Multilevel thoracic myelopathy: full-endoscopic solution. Illustrative case.

Thoracic myelopathy is relatively uncommon but, when present, causes significant disability. Early surgical intervention is often recommended for patients with myelopathy with compression at multiple levels. Surgical approaches and techniques for thoracic myelopathy have evolved from traditional open spine surgery to less invasive full-endoscopic spine surgery. This article reports an unusual presentation of a 31-year-old male with thoracic myelopathy due to thoracic disc herniation (TDH) at the T8-9 level and ossification of the ligamentum flavum at the T10-11 level that was managed using full-endoscopic spine surgery techniques in a single sitting. The presence of coexisting spinal disorders, that is, TDH and ossification of the posterior longitudinal ligament at noncontiguous spinal levels, makes surgical decision-making more complicated. Uniportal full-endoscopic spine surgery is a safe and effective surgical technique even for thoracic myelopathy. It is less invasive with minimal tissue and bone damage, better access to and visualization of the pathology, and minimal cord handling and is performed through small windows without destabilizing the spine, thus avoiding fusion. Anterior thoracic pathologies are better addressed through the transforaminal approach, whereas the interlaminar approach is preferred for posterior pathologies. Both of these approaches are complementary to each other with their own indications and advantages. https://thejns.org/doi/10.3171/CASE24413.

Anatomy and pathology of adductor canal (Hunter's canal).

Adductor canal (Hunter's canal) pathologies are often underdiagnosed, with the saphenous nerve being the most commonly affected. While uncommon, involvement of the femoral artery and vein can cause severe and irreversible complications if not detected early. Significant attention must be given to adductor canal pathologies because the musculoaponeurotic tunnel is predominantly fibrotic with minimal adipose tissue. As a result, any edema or space-occupying lesion can lead to early compression of the structures within the adductor canal. Incorporating adductor canal syndrome into the imagingdifferential diagnosisis essential. For diagnosing and sometimes managing these conditions. In this article, we describe theanatomy and spectrum of pathologies involving the Hunter's canal.

Clinical Outcomes of a Minimally Invasive Percutaneous Brostrom Technique without Arthroscopic Assistance.

Surgical management of chronic lateral ankle instability has traditionally been performed using an open technique. Arthroscopic-assisted and all-arthroscopic techniques have gained popularity as they have achieved strong clinical outcomes. However, they rely on the surgeon's arthroscopic skills and familiarity with arthroscopic anatomy. Recently, a minimally invasive percutaneous technique without arthroscopic assistance has been developed that incorporates the benefits of arthroscopy, such as minimal soft tissue disruption, without the additional requirements of performing an arthroscopic technique. The aim of the current study is to describe the minimally invasive percutaneous technique for chronic lateral ankle instability and report on its clinical outcomes. Fifty-four consecutive patients without intra-articular ankle pathology underwent lateral ligament repair for chronic ankle instability with a percutaneous technique at a single institution by a fellowship-trained foot and ankle surgeon. Foot Function Index (FFI) score was recorded pre-operatively and post-operatively at final follow-up. All patients had a minimum follow-up of 12 months. Post-operative complications and patient satisfaction were also recorded. A significant improvement (p < 0.001) in FFI compared to pre-operative values (from 55, SD 4.1, to 10, SD 1.9) was observed. A single patient required a return to the operating room for open revision with allograft reconstruction following a fall 2.5 months post-operatively. There were no other complications including infection or nerve injury. The overall rate of satisfaction after surgery was 98.1%, with one patient dissatisfied due to excessive ankle stiffness. The described minimally invasive percutaneous Brostrom procedure is safe and effective for the treatment of chronic lateral ankle instability without intra-articular ankle pathology.

Comparison of postoperative bleeding in pediatric tonsillectomy versus tonsillotomy

ObjectiveTonsillar surgery is a common intervention for pediatric obstructive sleep apnea and recurrent tonsillitis. This study compared postoperative bleeding incidence and severity following tonsillotomy and tonsillectomy at a single medical center. Study designA retrospective cohort study on 1984 pediatric patients (1–18 years old) who underwent surgery during 2004–2011 and 2019–2022. Tonsillectomy was performed during 2004–2011, while tonsillotomy was preferred for obstructive sleep apnea during 2019–2022. Tonsillectomy was performed using cold steel technique with complete removal of tonsillar tissue, while tonsillotomy was conducted using mono- or bipolar diathermy, preserving minimal tissue on the tonsillar capsule. SettingShaare-Zedek Medical Center, Faculty of Medicine, Hebrew University. MethodsOutcome measures included postoperative bleeding incidence and severity, surgery duration, hospitalization length, and readmission. ResultsTonsillotomy was conducted on 958 (48.3 %) patients, and tonsillectomy was performed on 1026 (51.7 %) patients. Obstructive sleep apnea was the only indication in 1553 (78.3 %) patients. Overall bleeding rate was lower following tonsillotomy (3.9 %) than tonsillectomy (9.5 %) (p < 0.001). Significantly more patients required surgical bleeding control post-tonsillectomy than post-tonsillotomy: 39 (3.7 %) vs. 5 (0.5 %), respectively (p < 0.001). Tonsillectomy resulted in higher readmission rates (11.8 % vs 6.1 %, p < 0.001), more blood transfusions (3 vs. 0), and higher postoperative hemoglobin diminution (1.57 ± 2 vs. 0.94 ± 1 g/dL, p = 0.035). The duration of the surgery was shorter for tonsillotomy (24.7 vs 26.5 min, p = 0.012). Tonsillectomy sustained higher bleeding rates for obstructive sleep apnea patients (7.0 % vs 3.9 %, p = 0.006). For recurrent tonsillitis patients, bleeding rates did not vary between year groups. Older age and tonsillectomy were the most significant risk factors for postoperative bleeding. ConclusionAmong children undergoing tonsillar surgery for obstructive sleep apnea, tonsillotomy was associated with a safer postoperative bleeding profile, reduced bleeding severity, and fewer readmissions compared to tonsillectomy.

Chromosome-scale genome assembly of the hunt bumble bee, Bombus huntii Greene, 1860, a species of agricultural interest.

The Hunt bumble bee, Bombus huntii, is a widely distributed pollinator in western North America. The species produces large colony sizes in captive rearing conditions, experiences low parasite and pathogen loads, and has been demonstrated to be an effective pollinator of tomatoes grown in controlled environment agriculture systems. These desirable traits have galvanized producer efforts to develop commercial Bombus huntii colonies for growers to deliver pollination services to crops. To better understand Bombus huntii biology and support population genetic studies and breeding decisions, we sequenced and assembled the Bombus huntii genome from a single haploid male. High-fidelity sequencing of the entire genome using PacBio, along with HiC sequencing, led to a comprehensive contig assembly of high continuity. This assembly was further organized into a chromosomal arrangement, successfully identifying 18 chromosomes spread across the 317.4 Mb assembly with a BUSCO score indicating 97.6% completeness. Synteny analysis demonstrates shared chromosome number (n = 18) with Bombus terrestris, a species belonging to a different subgenus, matching the expectation that presence of 18 haploid chromosomes is an ancestral trait at least between the subgenera Pyrobombus and Bombus sensu stricto. In conclusion, the assembly outcome, alongside the minimal tissue sampled destructively, showcases efficient techniques for producing a comprehensive, highly contiguous genome.

Development of keratin-based fibers fabricated by interfacial polyelectrolyte complexation for suture applications

Interfacial Polyelectrolyte Complexation (IPC) is a convenient way to produce composite, micro-scale fibers. In this paper, we report the successful development of novel keratin-based IPC fibers and also demonstrate the feasibility of using these fibers as sutures through a proof-of-concept in vivo study. Two composite fibers were produced: chitosan-keratin (CK) and keratin-keratin (KK). These fibers were evaluated for their physico-chemical, mechanical and biochemical properties. In the dry state, the CK fiber had a greater Young's modulus of about 2 GPa while the KK fiber registered a longer strain-at-break of about 100 % due to the strain-stiffening effect. Notably, the keratins were found to assemble into amyloids within the composite fibers based on Congo red staining and Wide-Angle X-Ray Scattering. Functionally, both fibers were malleable could be weaved, braided and knotted. When used as sutures to close incisional wounds in mice over 21 days, these fibers were found to elicit minimal host tissue response and were partially degraded over the duration. Interestingly, the KK fiber evoked a lower extent of immune cell response and fibrous capsule encapsulation that was comparable to commercial, non-absorbable Dafilon® sutures. This work demonstrated the possibility of producing keratin-based IPC fibers which may find practicality as medical sutures.

The Douglas-Bell Canada Brain Bank Post-mortem Brain Imaging Protocol

Magnetic resonance imaging (MRI) is a valuable non-invasive tool that has been widely used for in vivo investigations of brain morphometry and microstructural characteristics. Post-mortem MRIs can provide complementary anatomical and microstructural information to in vivo imaging and ex vivo neuropathological assessments without compromising the sample for future investigations. We have developed a post-mortem MRI protocol for the brain specimens of the Douglas-Bell Canada Brain Bank (DBCBB), the largest brain bank in Canada housing over 3000 neurotypical and diseased brain specimens, that allows for acquisition of high-resolution 3T and 7T MRIs. Our protocol can be used to scan DBCBB specimens with minimal tissue manipulation, allowing for feasibly scanning large numbers of post-mortem specimens while retaining the quality of the tissue for downstream histology and immunohistochemistry assessments. We demonstrate the robustness of this protocol despite the dependency of image quality on fixation by acquiring data on the first day of extraction and fixation, to over twenty years post fixation. The acquired images can be used to perform volumetric segmentations, cortical thickness measurements, and quantitative analyses which can be potentially used to link MRI-derived and ex vivo histological measures, assaying both the normative organization of the brain and ex vivo measures of pathology.

Less-Invasive Technique for Non-stabilized Mandibular Fracture in Mouse Models.

Non-stabilized fractures can be made at mandibular sites in mice, thus making it possible to analyze bone repair using an endochondral ossification mode. To most accurately reflect this process in vivo, it is necessary to have a standardized protocol to avoid excessive bone loss and soft tissue damage, particularly at the mandibular site, an anatomical site characterized by minimal access. To our knowledge, we describe for the first time a less-invasive protocol of non-stabilized mandibular fracture in mice. Adult mice are anesthetized with isoflurane and receive a preoperative dose of buprenorphine by subcutaneous injection. A submandibular approach is performed, with a skin incision made along the inferior border of the mandible. The masseter muscle is elevated in a subperiosteal plane along the mandibular ramus with a periosteal elevator. A vertical and complete fracture of the ramus is performed from the basilar border to the coronoid notch (between condylar and coronoid processes), using a piezoelectric bone surgery device under saline serum irrigation at the basilar edge and scissors to complete the fracture of the mandibular ramus. The skin approach is closed by silk sutures. This detailed procedure for non-stabilized mandibular fractures offers an efficient procedure allowing minimal bone loss and soft tissue damage. This technique ensures successful and consistent results to accurately reflect the process of endochondral bone repair in mouse models.

Switchable PAMAM megamers for deep tumor penetration and enhanced cell uptake

Nanoparticles fabricated to deliver anticancer drugs are usually designed to present optimized tumor penetration and cell internalization. However, there are some barriers and difficulties with most current technologies. Herein, size and charge switchable polyamidoamine (PAMAM) megamers (SChPMs) were prepared for the delivery of doxorubicin (DOX). SChPMs were fabricated by connecting PAMAM dendrimers with pH-sensitive bonds and surface PEGylation. At pH 7.4, the size and surface charge of these nanocarriers were approximately 100 nm and + 0.75 mV, but at the acidic extracellular pH of tumor cells (pH 6.5), their size were reduced dramatically (15 nm) and their surface charge increased to +6.7 mV. Cell studies confirmed that alteration of the size and surface charge enhanced their penetration into multicellular spheroids and cell internalization. These megamers, in addition to delivering the drug to the deeper areas of the tumor, could powerfully overcome physiological resistance to anthracycline-based drugs. The nanocarrier revealed enhanced antitumoral activity in animal studies. Toxicology studies and histopathological assessments of vital tissues of 4 T1 tumor bearing mice indicated minimal tissue damage when DOX-loaded SChPMs (DSChPMs) were used. It can be concluded that the versatile and agile nanocarriers developed in this study could be considered for further investigations into their clinical application.

Laying the foundations for high-quality mortality surveillance in Sierra Leone: Early learnings from the Child Health and Mortality Prevention Surveillance (CHAMPS) Network

Background More than four million child deaths occur annually; most are neither adequately documented nor investigated. The Child Health and Mortality Prevention Surveillance (CHAMPS) program was launched in Sierra Leone (SL) to generate high-quality data to determine definitive causes of stillbirths and under-five mortality (U5M) to inform decision-makers. Despite the multiple challenges of a greenfield research site, we highlight the experience of setting up a high-quality mortality surveillance (MS) system, including the viability of Minimal Invasive Tissue Sampling (MITS). Methods To establish the MS program, we implemented qualitative research and community entry, a sensitive system for timely identification and notification of deaths and followed CHAMPS standard operating procedures for investigating deaths and assigning accurate and definitive causes of death. CHAMPS in SL was implemented in four phases during 2017-2019 by a consortium. Enrolled stillbirths and U5M underwent verbal autopsy, clinical-data-abstractions, MITS, microbiology, molecular and histopathological diagnoses, and Determination of Cause of Death (DeCoDe). Results CHAMPS achieved a 93% consent rate, capitalizing on existing Ministry of Health infrastructure, community involvement, and local ownership. As of December 2022, 3,433 deaths were registered, with 1,056 (31%) eligible for enrolment. Of 439 cases DeCoDed, 402 (92%) of case-families had received feedback on the cause of death. Using findings and recommendations from the DeCoDe experts, CHAMPS is implementing interventions to reduce stillbirths and U5M at CHAMPS SL, including clinical review meetings, provision of emergency drugs and routine child death audits. Conclusion Implementing innovative MS in a challenging context, such as SL, is possible. Building on local knowledge and infrastructure has enabled the CHAMPS project to achieve remarkably high consent rates, given the cultural, religious and sensitivity challenges surrounding seeking consent for MITS from caregivers who have just lost a child. The programme has invested significantly in upscaling local technical capacity for surveillance and laboratory diagnostics.

Optical gain and related proerties of GaSbN/GaSb quantum-well laser: numerical approach

Currently, lasers are still of ongoing interest. They are used in a large range of practical applications in our day life and across various fields. Utilizations include industry such as in cutting, welding, drilling, and engraving of various materials, in medicine such as in surgery for precise cutting and cauterization with minimal tissue damage, in ophthalmology, dentistry for removing tooth decay and reshaping dental tissues, in high-speed data transmission through optical fibers, in science and research (spectroscopy, metrology and holography) and for creating visual displays, etc. The optical gain of a laser diode is a key characteristric that exhibits the performances of lasers. In the present work, we investigated the optical gain of a strained GaSbN/GaSb quantum well laser with nitrogen concentration of 3%. This low nitrogen concentration makes our GaSbN alloy a dilute one. Our analysis focused on the impact of carrier density and quantum well width on optical gain of the laser device being studied. Additionally, we determined the relationship between quantum well width and emitted wavelength. Our numerical results indicate an effective correlation between optical gain and both carrier density and quantum well width. Furthermore, inasing the quantum well width led to a longer emitted wavelength. The laser demonstrated emission within the infrared-red spectrum.

Assessing functional and radiological outcomes: open reduction and internal fixation vs. minimally invasive plate osteosynthesis for humerus shaft fractures-a prospective comparative study.

To analyse and compare the functional and radiological outcome of different methods of surgical management of humerus shaft fractures in 30 patients treated by conventional open reduction and internal fixation (ORIF) or minimally invasive plate osteosynthesis (MIPO). This prospective interventional study was conducted among 30 patients by dividing into two equal groups over oneyear and sixmonths. All patients were followed up for a minimum of at least sixmonths. Radiological outcome was assessed using fracture union in serial radiographs and functional outcome was measured using DASH scoring. The majority of patients (26.7%) were between 18 to 30years, overall mean age was 44.4years, most of the patients (50%) had 12A3 AO type fractures, and 73.3% of patients had injuries following two-wheeler road traffic accidents. On comparing multiple factors, we found a statistically significant reduction of intra-operative blood loss in MIPO compared to ORIF. Though time taken for fracture union, functional outcome and complication rate were better in MIPO when compared to ORIF, these differences were not statistically significant. two patients in the MIPO group and one patient in the ORIF group had a peri-implant fracture following slip and fall again within the study period and underwent Revision plating. Excluding cases of peri-implant fractures, out of 13 patients in the MIPO group, only one patient developed fracture non-union. Of 14 patients in the ORIF group, three developed fracture non-union. MIPO is a safe, reproducible, efficient and good if not a better alternative to ORIF as it offers good radiological and functional outcomes with advantages of minimal soft tissue damage, minimal blood loss, better cosmesis, no incidence of radial nerve palsy and with few concerns such as the need for fluoroscopy, and a learning curve.

A simple suture technique to repair iatrogenic iridodialysis post cataract surgery: A case report

Disinsertion of iris from its attachment is called iridodialysis. Symptomatic and large iridodialysis often requires repair. Repair of iridodialysis is complex and often require special instruments and good surgical expertise. We describe a simple suture technique to repair an iatrogenic iridodialysis caused during small incision cataract surgery in a 62 year-old patient. This technique is simple and involves very minimal tissue handling. The primary aim of us doing this procedure is the functional and cosmetic result which can be obtained in the same sitting as the primary procedure with common available instruments.

Steerable ultrasonic propulsion of rigid objects based on circular pressure modulation of a focused sectorial transducer array

As a common disease of human urinary system, the high prevalence and incidence rate of renal calculus have brought heavy burden to society. Traditional ultrasonic lithotripsy struggles with the comprehensive elimination of residual fragments and may inadvertently inflict renal damage. Although focused ultrasound can propel stones by the acoustic radiation force (ARF) with minimal tissue damage and enhanced passage rate, it is still lack of the accurate control for calculi at different locations. A circular pressure modulation approach for steerable ultrasonic propulsion of rigid objects is developed based on a sector-array of focused transducers. The ARF exerted on on-axis rigid spheres (stones) is derived based on acoustic scattering. It is proved that the ARF of focused fields exhibits an axial distribution of increasing followed by decreasing with the peak slightly beyond the focus. As the sphere radius increases, the ARF exerted on spheres at the focus increases accordingly with a decreasing growth rate. Inclined propulsion can be realized by the circular binary pressure modulation with the deflection increased by expanding the angle of power-off sector sources. The maximum deflection angle approaching 60° is determined by the F-number and element number of the sector-array. Experimental propulsions of steel balls are conducted using an 8-element sector-array with motion trajectories captured by a high-speed camera. Distributions of the motion speed and acceleration for steel balls of different radii are calculated through image processing. The ARF of mN level and the deflection angle of 12° are demonstrated by the successful propulsion of steel balls. This research provides an effective and flexible approach of steerable stone propulsion using an ultrasonic power supply without the complex control in amplitude or phase and the high-precision motion of the sector-array, hence promoting the practical application in non-invasive treatment of stones.

Hybrid scaffolds for bone tissue engineering: Integration of composites and bioactive hydrogels loaded with hDPSCs

Bone tissue regeneration remains a significant challenge in clinical settings due to the complexity of replicating the mechanical and biological properties of bone environment. This study addresses this challenge by proposing a hybrid scaffold designed to enhance both bioactivity and physical stability for bone tissue regeneration. This research is the fisrt to develop a rigid 3D structure composed of polycaprolactone (PCL) and hydroxyapatite nanoparticles (nHA) integrated with a bioink containing human dental pulp stem/stromal cells (hDPSCs), alginate, nHA and collagen (Col). The biofabricated constructs were extensively characterized through cytocompatibility tests, osteogenic differentiation assessment, and biocompatibility evaluation in a rat model. In vitro results demontrated that the hybrid scaffolds presented significantly higher cell viability after 168 h compared to the control group. Furthermore, the hybrid scaffolds showed increased osteogenic differentiation relative to other groups. In vivo evaluation indicated good biocompatibility, characterized by minimal inflammatory response and successful tissue integration. These findings highlight the scaffold's potential to support bone tissue regeneration by combining the mechanical strength of PCL and nHA with the biological activity of the alginate-nHA-Col and hDPSCs bioink. The current study provides a promising foundation for the development of biomaterials aimed at improving clinical outcomes in bone repair and regeneration, particulary for the treatment of critical-size bone defects, targeted drug administration, and three-dimensional models for bone tissue engineering.