Soft Silicone Research Articles

Educational Soft Underwater Robot with an Electromagnetic Actuation.

As demonstrated by the Soft Robotics Toolkit Platform, compliant robotics pose an exciting educational opportunity. Underwater robotics using soft undulating fins is an expansive research topic with applications such as exploration of underwater life or replicating 3d swarm behavior. To make this research area accessible for education we developed Educational Soft Underwater Robot with Electromagnetic Actuation (ESURMA), a humanoid soft underwater robot. We achieved advances in simplicity, modularity, and performance by implementing electromagnetic actuation into the caudal fin. An electromagnet, including electronics, is placed in a waterproof housing, and permanent magnets are embedded in a soft silicone cast tail. The force from their magnetic interaction results in a bending movement of the tail. The magnetic actuation is simple to implement and requires no mechanical connection between the actuated component and the electrically controlled coil. This enables robust waterproofing and makes the device fully modular. Thanks to the direct and immediate transmission of force, experimental flapping frequencies of 14 Hz were achieved, an order of magnitude higher compared to pneumatically actuated tails. The completely silent actuation of the caudal fin enables a maximum swimming speed of 14.3 cm/s. With its humanoid shape, modular composition, and cost efficiency ESURMA represents an attractive platform for education and demonstrates an alternative method of actuating soft structures.

Examining the Clinical Outcomes of a Soft Silicone Multilayer Foam Dressing for Exudate Management in US Hospitals: It Is Time to Optimize Dressing Change Frequency

Background. Acute and chronic wounds in the acute hospital setting are commonly managed with soft silicone multilayer foam dressings (SSMFDs). While many SSMFDs are indicated for wear time of up to 7 days, they are often changed more frequently. Objective. To use real-world data on dressing change practices and clinical outcomes to examine whether a built-in indicator on a proprietary SSMFD could reduce unnecessary dressing changes. Materials and Methods. Health care professionals (HCPs) were screened and recruited from a health care research panel to complete per wound data capture forms. Outcomes reported included dressing wear time, healing rates, dressing change frequency, user satisfaction, and adverse events. Outcomes were reported as an aggregated data set. Results. A total of 53 wounds were analyzed. The mean treatment period was 23.83 days, which included dressing changes every 2 to 3 days on average. Of the 53 cases analyzed, the unique change indicator on the SSMFD was used to guide dressing change frequency 98% of the time. Overall, 21% of wounds completely healed (n = 11), 70% (n = 37) showed improvement, 9% (n = 5) were static, and 0% deteriorated. Conclusion. Real-world data on use of the proprietary SSMFD in an acute setting indicates that the SSMFD can allow for the optimization of dressing change protocols to enable appropriate dressing change frequency, allowing for undisturbed healing and maximizing HCP and dressing resources.

Meko podlaganje imedijatne totalne proteze - prikaz slučaja

Introduction: With the placement of dental implants in edentulous patients, creating and adapting immediate dentures is crucial to allow patients to perform basic physiological functions during the osseointegration period without affecting implant healing. This report presents a case of direct soft lining of immediate complete dentures following implant placement. Case Report: Six dental implants were inserted in the upper jaw, while the patient retained natural teeth in the lower jaw. An immediate complete denture was fabricated and adjusted for the upper jaw. The prosthesis base was prepared and processed to accommodate soft lining material. Adhesive was applied to the prepared base, followed by silicone application for soft fitting onto the prosthesis base, which was then inserted into the patient's mouth. After three minutes, the denture was removed, and soft lining treatment of the immediate complete denture was completed. Conclusion: Direct soft lining facilitated patient adaptation to the immediate prosthesis and supported safer healing and osseointegration until definitive work could be completed. The addition of a soft silicone layer reduced pressure on the residual alveolar ridge and improved adhesion of the immediate prosthesis.

Outcomes and patient satisfaction after Penuma silicone implant surgery via two surgical approaches.

The Penuma is a soft silicone penile implant designed for cosmetic enhancement of the flaccid penis in men who have normal erections. The goal of this study is to report outcomes on patient satisfaction at least 6 months after Penuma subcutaneous penile implant for cosmetic enhancement of the penis, and to determine if modifications in surgical approach resulted in reduction in postoperative complications. Penile measurements, adverse events, and patient satisfaction were compared between patients undergoing the new lateral scrotal incision versus the traditional infrapubic approach. A retrospective chart review was performed on all patients who underwent a Penuma implant by a single surgeon from April 2019 to December 2022. A 26-item non-validated device-specific questionnaire was sent to patients at least 6 months after the date of their initial surgery. A total of 92 cases were performed by a single surgeon. The average increase in flaccid length was 2.5 cm (±2.2), representing a 44% increase (p < 0.01). The average increase in girth was 3.1 cm (±1.8 cm), a 32% change (p < 0.01). Seroma requiring drainage occurred in 12%. 7% of patients required operative revision of the implant. When assessed by surgical approach, the revision rate was significantly higher in infrapubic patients (13% vs 2%, p < 0.05). The implant removal rate was also significantly higher when the infrapubic approach was used (21% vs 6%, p < 0.05). 82% of patients reported being satisfied or very satisfied with their postoperative penile appearance. 75% of patients would undergo surgery again. The subcutaneous Penuma penile implant appears to improve satisfaction with regard to the appearance of the penis and is a viable option for men who desire to enhance flaccid penile length and girth. Furthermore, the lateral scrotal surgical approach appears to have a lower postoperative complication rate.

A Tunable Soft Silicone Bioadhesive for Secure Anchoring of Diverse Medical Devices to Wet Biological Tissue (Adv. Mater. 3/2024)

A Tunable Soft Silicone Bioadhesive for Secure Anchoring of Diverse Medical Devices to Wet Biological Tissue (Adv. Mater. 3/2024)

Accuracy of formula-based volume and image segmentation-based volume in calculation of preoperative cystic jaw lesions’ volume

ObjectiveThe aim of this study was to assess the accuracy of formula-based volume measurements and the 3D volume analysis with different software packages in the calculation of preoperative cystic jaw lesions’ volume. The secondary aim was to assess the reliability and the accuracy of 3 imaging software programs for measuring the cystic jaw lesions' volume in CBCT images.Materials and methodsThis study consisted of two parts: an in vitro part using 2 dry human mandibles that were used to create simulated osteolytic lesions to assess the accuracy of the volumetric analysis and formula-based volume. As a gold standard, the volume of each bone defect was determined by taking an impression using rapid soft silicone (Vinylight) and then quantifying the volume of the replica. Afterward, each tooth socket was scanned using a high-resolution CBCT. A retrospective part using archived CBCT radiographs that were taken from the database of the outpatient clinic of the oral and maxillofacial radiology department, Faculty of Dentistry, Minia University to assess the reliability of the 3 software packages. The volumetric data set was exported for volume quantification using the 3 software packages (MIMICS-OnDemand and InVesalius software). Also, the three greatest orthogonal diameters of the lesions were calculated, and the volume was assessed using the ellipsoid formula. Dunn’s test was used for pair-wise comparisons when Friedman’s test was significant. The inter-examiner agreement was assessed using Cronbach’s alpha reliability coefficient and intra-class correlation coefficient.ResultsRegarding the results of the retrospective part, there was a statistically significant difference between volumetric measurements by equation and different software (P value < 0.001, Effect size = 0.513). The inter-observer reliability of the measurements of the cystic lesions using the different software packages was very good. The highest inter-examiner agreement for volume measurement was found with InVesalius (Cronbach’s alpha = 0.992). On the other hand, there was a statistically significant difference between dry mandible volumetric measurements and Gold Standard. All software showed statistically significantly lower dry mandible volumetric measurements than the gold standard.ConclusionComputer-aided assessment of cystic lesion volume using InVesalius, OnDemand, and MIMICS is a readily available, easy to use, non-invasive option. It confers an advantage over formula-based volume as it gives the exact morphology of the lesion so that potential problems can be detected before surgery. Volume analysis with InVesalius software was accurate in determining the volume of simulated periapical defects in a human cadaver mandible as compared to true volume. InVesalius software proved that open-source software can be robust yet user-friendly with the advantage of minimal cost to use.

A Tunable Soft Silicone Bioadhesive for Secure Anchoring of Diverse Medical Devices to Wet Biological Tissue.

Silicone is utilized widely in medical devices for its compatibility with tissues and bodily fluids, making it a versatile material for implants and wearables. To effectively bond silicone devices to biological tissues, a reliable adhesive is required to create a long-lasting interface. BioAdheSil, a silicone-based bioadhesive designed to provide robust adhesion on both sides of the interface is introduced here, facilitating bonding between dissimilar substrates, namely silicone devices and tissues. The adhesive's design focuses on two key aspects: wet tissue adhesion capability and tissue-infiltration-based long-term integration. BioAdheSil is formulated by mixing soft silicone oligomers with siloxane coupling agents and absorbents for bonding the hydrophobic silicone device to hydrophilic tissues. Incorporation of biodegradable absorbents eliminates surface water and controls porosity, while silane crosslinkers provide interfacial strength. Over time, BioAdheSil transitions from nonpermeable to permeable through enzyme degradation, creating a porous structure that facilitates cell migration and tissue integration, potentially enabling long-lasting adhesion. Experimental results demonstrate that BioAdheSil outperforms commercial adhesives and elicits no adverse response in rats. BioAdheSil offers practical utility for adhering silicone devices to wet tissues, including long-term implants and transcutaneous devices. Here, its functionality is demonstrated through applications such as tracheal stents and left ventricular assist device lines.

Multimode coaxial extrusion of segmented core-shell structures for soft metamechanics and biomimetic applications

The unique ability to combine versatile materials via additive manufacturing greatly enhances the functionalities of soft machines. However, manufacturing for multi-material devices often involves complex and redundant procedures. Herein, we develop a multimode coaxial direct ink writing method for efficient 3D printing of multi-material filaments in the form of core-shell material distribution at millimeter scales. Through simulations and experiments, essential printing parameters, such as extrusion pressure and deposition speed combinations, are investigated to control compositions simultaneously. As exemplars, we fabricate soft lattices presenting tunable mechanical responses by printing soft and tough silicone in a single pass. We also demonstrate bio-mimetic potentials by fabricating soft fingers and magnetic shape-shifting structures with multiple functional materials. Our method is expected to provide a new paradigm for designing and manufacturing the rapid prototyping of soft functional machines.

Innovative Use of Mouth Props/Bite Blocks in Postoperative Mouth Opening Exercises.

Postoperative jaw physiotherapy in the form of mouth opening exercises is an integral part of surgical treatment in oral submucous fibrosis and temporomandibular joint ankylosis. The literature has outlined multiple physical therapy modalities and modifications to aid in assisted mouth-opening exercises. To overcome shortcomings associated with the use of conventional devices, the authors describe an innovative use and modification of a prefabricated soft silicone bite block/mouth prop as an adjunct to the devices to aid in achieving optimal mouth opening.

Hydrosilylation Adducts to Produce Wide-Temperature Flexible Polysiloxane Aerogel under Ambient Temperature and Pressure Drying.

Despite incorporation of organic groups into silica-based aerogels to enhance their mechanical flexibility, the wide temperature reliability of the modified silicone aerogel is inevitably degraded. Therefore, facile synthesis of soft silicone aerogels with wide-temperature stability remains challenging. Herein, novel silicone aerogels containing a high content of Siare reported by using polydimethylvinylsiloxane (PDMVS), a hydrosilylation adduct with water-repellent groups, as a "flexible chain segment" embedded within the aerogel network. The poly(2-dimethoxymethylsilyl)ethylmethylvinylsiloxane (PDEMSEMVS) aerogelis fabricated through a cost-effective ambient temperature/pressure drying process. The optimizedaerogel exhibits exceptional performance, such as ultra-low density (50mg cm-3), wide-temperature mechanical flexibility, and super-hydrophobicity, in comparison to the previous polysiloxane aerogels. A significant reduction in the density of these aerogels is achieved while maintaining a high crosslinking density by synthesizing gel networks with well-defined macromolecules through hydrolytic polycondensation crosslinking of PDEMSEMVS. Notably, the pore/nanoparticle size of aerogels can be fine-tuned by optimizing the gel solvent type. The as-prepared silicone aerogels demonstrate selective absorption, efficient oil-water separation, and excellent thermal insulation properties, showing promising applications in oil/water separation and thermal protection.

Magnetic training of the soft magnetorheological elastomers

The effect of repetitive quasi-static magnetisation of a magnetorheological elastomer on its magnetic response is discussed. Typical components of this material, namely soft silicone rubber and carbonyl iron powder, are used to produce magnetically sensitive composite samples. The composite specimens are examined by vibrating sample magnetometry. The influence of the elasticity of the composite matrix on the change in magnetic differential susceptibility of the material as a function of the number of repeated magnetisation cycles is evaluated. The soft matrix elastomers are characterised by the presence of maxima in the initial part of the differential susceptibility curves. The sample magnetisation values corresponding to such maxima vary with the number of magnetisation cycles. In addition, the initial magnetic susceptibility curves of soft samples obtained at different polarity of the applied field are not symmetrical. Symmetry is obtained by performing several subsequent magnetisation cycles. The differential susceptibility curves are affected by both reversible and irreversible processes related to particle mobility in the matrix. The magnetic response of composite samples with rigid matrices is more similar to that of classical soft magnetic materials.

Effect of "micromovement" in preventing intraoperative acquired pressure injuries among patients undergoing surgery in supine position.

To explore the clinical effect of "micromovement" in preventing intraoperative acquired pressure injures (IAPIs) among patients experiencing surgery in supine position. A total of 200 patients accepting elective surgery in supine position from 10 May 2023 to 4 July 2023 at Shulan (Hangzhou) Hospital were selected and randomized into two groups (experimental group, n = 100; control group, n = 100). For control group patients, soft silicone foam dressing was applied to the sacrococcygeal region. On the basis of the treatment for control group patients, "micromovement" was implemented among experimental group patients. During this process, the operating table was tilted for 15° leftwards and rightwards alternately every 1 h, and the tilt angle was maintained for 5 min to prevent IAPIs. Finally, comparisons between the two groups were made in terms of the sacrococcygeal IAPI incidence, relative temperature differences (ΔT) on sacrococcygeal skin, and job satisfaction of nurses. Compared with control group patients, patients from the experimental group exhibited lower IAPI incidence (2% vs. 10%), reduced ΔT between the sacrococcygeal skin and surrounding normal skin [0 (-0.1, 0.1) vs. 0.2 (-0.2, 0.4)], and elevated job satisfaction of nurses (80% vs. 66%). All the differences were statistically significant (p < 0.05). "Micromovement" implemented intraoperatively among patients receiving surgery in supine position is able to lower the IAPI incidence by five times and elevate job satisfaction of nurses.

The incidence of intraoperatively acquired pressure injuries in the park-bench position was reduced by applying soft silicone multilayer foam dressings.

The Park-Bench Position (PBP) is associated with a high incidence rate of intraoperatively acquired pressure injuries (IAPIs). Preventive measures must be established to prevent the development of IAPIs. We investigated the risk factors for PBP by applying a soft silicone multilayered foam dressing (SMD) under core temperature management to prevent IAPIs. We conducted a prospective, single-centre, open-label observational study of patients undergoing elective neurosurgery operations using PBP in a university hospital in Japan. The incidence rate of IAPIs in this study was compared with that in our two previous studies, in which a film dressing was applied and core temperature management was not performed. IAPIs developed in 90 patients (6.7%); in the lateral thoracic region in five patients and the iliac crest region in one patient. The operative time (every 1 h: p = 0.0001, OR: odds ratio 3.62, 95% CI: confidence interval 1.73-11.42) was significantly associated with the incidence of IAPIs. In our two previous studies, the incidence rate of IAPIs was 11.0% and 24.1%, respectively, when film dressing was used. SMD may weaken the involvement of risk factors in IAPIs.

Assessment of the mechanical behavior of bonded glass-to-glass transparent epoxy adhesive joint at elevated temperatures for load-bearing elements

Glass is increasingly used as a structural material in buildings, not only for enclosing spaces but also for bearing loads. To meet architect requirements for a uniform structure without appearance disturbance, adhesively bonded joints are preferred over mechanical fasteners. However, in the construction industry, most technical guidelines cover only soft structural silicone sealants, while stiffer adhesives like epoxy resins are not considered. Alternatively, the specific transparent epoxy adhesives offer a high potential for bonded glass assemblies, enabling thinner joints and a fully transparent junction. Indeed, under real service conditions, elevated temperatures are one of the worst factors affecting the mechanical properties of structural bonded joints. Therefore, in this paper, an experimental program was conducted to evaluate the performance of transparent bonded glass joints with epoxy resin over a wide range of temperatures. Tensile and shear tests were performed on bulk-cured adhesive samples and bonded glass-to-glass block shear specimens respectively, at room temperature (RT), 40, 60, and 80 °C. The differences in surface characteristics such as roughness, wettability, and surface free energy (SFE) between both glass sides were examined. The results showed that tensile and shear strengths decreased with increasing temperatures. Furthermore, the shear strength was influenced by the surface properties of the glass sides. At all tested temperatures, the rougher bonded glass side specimens revealed higher shear strength coupled with a mixed failure while a loss of adhesion characterised the smoother glass surfaces.

Modulating the Configurations of "Gel-Type" Soft Silicone Rubber for Electro-Mechanical Energy Generation Behavior in Wearable Electronics.

Electro-mechanical configurations can be piezo-electric transducers, triboelectric generators, electromagnetic induction, or hybrid systems. Our present study aims at developing energy generation through the piezoelectric principle. Gel-type soft SR with Shore A hardness below 30 was used as a versatile material for an elastomeric substrate. Also, multi-wall carbon nanotube (MWCNT), and diatomaceous earth (DE) were used as reinforcing fillers. This "gel-type" soft SR has crosslinking polymer networks with silicone encapsulated within its structure. Mechanical properties such as modulus or stretchability are of utmost importance for such devices based on "gel-type" soft. From the experiments, some of the mechanical aspect's values are summarized. For example, the stretchability was 99% (control) and changes to 127% (3 phr, MWCNT), 76% (20 phr DE), and 103% (20 phr hybrid). From electro-mechanical tests, the output voltage was 0.21 mV (control) and changed to 0.26 mV (3 phr, MWCNT), 0.19 mV (20 phr DE), and 0.29 mV (20 phr hybrid). Moreover, from real-time biomechanical human motion tests in "gel-type" soft-based composites, a relationship among output voltage from machine to human motions was established. Overall, these configurations make them promising against traditional portable devices such as batteries for small power applications such as mobile phones.

Liquid metal-based strain-sensing glove for human-machine interaction

Soft and stretchable strain sensors have aroused great interest in research and engineering fields due to their promising application potential in many areas, including human-machine interface and healthcare monitoring. However, developing stable, strain-sensitive, and fatigue-resistant wearable strain sensors remains challenging. Herein, we report a low-cost strain-sensing glove based on a commercial nitrile glove and liquid metal as both sensing units and circuit/interconnects, with excellent response to strains and great stability in long-term use. The liquid metal sensing circuit is prepared by scraping the liquid metal slurry in situ on glove fingers, followed by soft silicone encapsulation. The whole process does not involve toxic chemicals, so no strict requirements on the operating environment are necessary. The strain-sensing glove is capable of real-time monitoring of finger gestures in a very sensitive and accurate way, which exhibits great application potential as a soft controller in manipulating the machine hand to achieve related human-machine interaction.

Intrauterine Vacuum-Induced Haemorrhage-Control Device: A Novel Approach For Pph.

Madam, Postpartum haemorrhage (PPH), defined as postpartum blood loss of &gt; 1000 mL, is a life-threatening emergency and the leading cause of maternal mortality accounting for 25% of maternal deaths worldwide (1). PPH can lead to significant morbidity, including shock, ARDS, coagulopathy, infertility due to hysterectomy, and even mortality (4). Uterine atony is the most common cause, accounting for 80% of all cases of PPH (1) (2). Active management of the third stage of labour consisting of a triad of oxytocin, controlled cord traction, and uterine massage can reduce the incidence of PPH by 60% (5). If abnormal uterine bleeding ensues, PPH protocols are activated, including uterine balloon tamponade, uterine packing, uterine artery embolization, or hysterectomy (1, 2). The Jada System (novel intrauterine vacuum-induced haemorrhage-control device) approved by the U.S. FDA in August 2020, utilizes a low-level vacuum to induce negative pressure in the uterine cavity that facilitates uterine contraction to constrict myometrial blood vessels that can help with uterine atony (1). The device is used in patients with PPH where standard PPH treatments have failed or are contraindicated (1). It is a soft medical-grade silicone that attenuates the risk of tissue trauma and can be placed trans-vaginally after 3 cm of cervical dilation after vaginal birth and C-section (1,2). Ultrasound is used to check correct device placement, along with real-time quantification of the expelled blood from the uterine cavity into the graduated canister. The device can be placed for 1.5 hours to 24 hours inside the uterus. The device can be removed after evaluation of evacuated blood and palpation for a firm uterus, both signifying control of the hemorrhage (2). A First-in-Human (FIH) feasibility study conducted in Indonesia on 10 participants with atony-related PPH showed that the device was placed effectively, and bleeding was controlled in under 2 minutes with no unfavorable outcome in any participants (1) (3). The study was conducted with 107 participants of which two-thirds had atony-related PPH with failed medical treatment (1). The Per Protocol showed a 99% success rate in effectively controlling PPH (2). Bleeding halted in a minimum of 3 minutes, the treatment duration was around 3.2 hours and 98% of users regarded it as convenient to use (1). Adverse events included endometritis and vaginal infections all of which were resolved with adequate treatment (2). ---Continue

Use of 3D-printing cerebral aneurysm model assisting microcatheter shaping in neurovascular intervention technique training

BackgroundMicrocatheter shaping plays a vital role in coil embolization of cerebral aneurysms, while the complicated method and insufficient training opportunities make it difficult for junior neurovascular clinicians to master this technique. In this program, we constructed a novel training method and assessment system for microcatheter shaping in coil embolization of cerebral aneurysms with 3D technique, and evaluated its efficacy for microcatheter shaping training in junior neurovascular clinicians. MethodsPatient-specific models for cerebral aneurysms in different locations and with different morphologies were selected by experienced senior neurovascular clinicians. The solid polylactic acid model and the soft hollow crystal silicone model of intracranial aneurysms were then made separately for shaping reference and assessment in the training course. Twelve residents without prior experience of microcatheter shaping and 25 neurovascular clinicians who have in vivo experience of microcatheter shaping on 3–5 occasions were selected for this training program and randomly divided into the traditional training group and the experimental training group. Four senior neurovascular clinicians assisted and guided the trainees in two groups and evaluated the time and accuracy of microcatheter shaping. ResultsEighteen trainees were assigned to the traditional training group, among which 4 had prior experience in microcatheter shaping. The other 19 were assigned to the experimental training group, including 8 with prior experience. No statistical difference in the distribution of experienced students between the two groups was noted(P = 0.295). After the training session, the shaping time was found shorter in the experimental training group than that in the traditional training group (40.3.5 ± 16.2 s vs. 54.2 ± 16.4 s, P = 0.014), while the shaping score was found higher in the experimental training group than that in the traditional training group (4.4 ± 0.5 vs. 2.6 ± 1.2, P < 0.001). Specifically, for the trainees without prior experience, the experimental training group also showed less time consumption and higher score (Time: 52.7 ± 7.7 vs. 61.5 ± 9.5, P = 0.02; Score 4.1 ± 0.5 vs. 2.3 ± 1.1, P < 0.01). Meanwhile, for the trainees with prior experience, the advantage was noted in shaping score (4.7 ± 0.3 vs. 3.9 ± 0.6, P < 0.01) but not in time consumption (23.3 ± 4.4 vs. 28.5 ± 3.9, P = 0.07). ConclusionThis training program is quite effective at teaching junior neurovascular physicians the essential surgical abilities required for coiling cerebral aneurysms.

Real-time multiaxial strain mapping using computer vision integrated optical sensors

Soft strain sensors pose great potential for emerging human–machine interfaces. However, their real-world applications have been limited due to challenges such as low reproducibility, susceptibility to environmental noise, and short lifetimes, which are attributed to nanotechnologies, including microfabrication techniques. In this study, we present a computer vision-based optical strain (CVOS) sensor system that integrates computer vision with streamlined microfabrication techniques to overcome these challenges and facilitate real-time multiaxial strain mapping. The proposed CVOS sensor consists of an easily fabricated soft silicone substrate with micro-markers and a tiny camera for highly sensitive marker detection. Real-time multiaxial strain mapping allows for measuring and distinguishing complex multi-directional strain patterns, providing the proposed CVOS sensor with higher scalability. Our results indicate that the proposed CVOS sensor is a promising approach for the development of highly sensitive and versatile human–machine interfaces that can operate long-term under real-world conditions.

A Tactile Skin System for Touch Sensing with Ultrasound Tomography.

The tomographic imaging method is promising in large-area touch-sensing applications. This paper presents a new type of such touch sensor using ultrasonic tomography (UST) via sound attenuation imaging. UST is gaining popularity as a portable, fast, and inexpensive imaging system for medical and industrial applications. UST can be developed in different operation modes. A transmission mode UST is being investigated as a force- and touch-sensitive skin. A prototype skin sensor was developed in a 200 mm diameter circular UST array containing two sets of 16 transducers, with one operating at a central frequency of 40 kHz and the other at 300 kHz. The extension of the sensor in terms of dimension, up to 400 mm diameter, and number of sensors, up to 32 transducers, is possible where eight points of contact were reconstructed successfully. The medium contains a 20 mm high water region, and a soft silicone membrane covers the liquid region. When touchpoints or forces are applied to the soft skin of the membrane, the sound pathway is disrupted, resulting in an image of the touch position and touch force intensity using a tomographic UST algorithm. Several static and dynamic experiments are conducted to demonstrate this novel application of UST. In addition, a correlation analysis is carried out to establish the force quantification potential for the UST-based tactile skin.