Intraperitoneal aerosolized drug delivery: Technology, recent developments, and future outlook

Nanotherapy to Reshape the Tumor Microenvironment: A New Strategy for Prostate Cancer Treatment

Prostate cancer (PCa) is the second most common cancer in males worldwide. Androgen deprivation therapy (ADT) is the primary treatment method used for PCa. Although more effective androgen synthesis and antiandrogen inhibitors have been developed for clinical practice, hormone resistance increases the incidence of ADT-insensitive prostate cancer and poor prognoses. The tumor microenvironment (TME) has become a research hotspot with efforts to identify treatment targets based on the characteristics of the TME to improve prognosis. Herein, we introduce the basic characteristics of the PCa TME and the side effects of traditional prostate cancer treatments. We further highlight the emergence of novel nanotherapy strategies, their therapeutic mechanisms, and their effects on the PCa microenvironment. With further research, clinical applications of nanotherapy for PCa are expected in the near future. Collectively, this Review provides a valuable resource regarding the various nanotherapy types, demonstrating their broad clinical prospects to improve the quality of life in patients with PCa.

Second annual report from the ISSPP PIPAC database

Objectives

To monitor the results of PIPAC directed therapy based on data from the International Society for the Study of the Pleura and Peritoneum (ISSPP) PIPAC database.

Methods

Analysis of data from patients entered between June 15th, 2020, and February 28th, 2023.

Results

Twelve centers reported 2,456 PIPAC procedures in 809 patients (median 2, range 1-18) with peritoneal metastasis (PM) from different primary tumors. Approximately 90 % had systemic chemotherapy prior to PIPAC. Twenty-eight percent were treated in prospective protocols. Overall non-access rate was 3.5 %. Concomitant surgical procedures were performed during PIPAC in 1.6 % of the patients. Median length of stay was 2 days. A total of 95 surgical complications were recorded, but only 22 % of these were graded ≥3b. Seventeen-hundred-and-three adverse events were noted, and 8 % were classified ≥3. The rate of complete or major histological response (peritoneal regression grade score, PRGS≤2) increased between the first and the third PIPAC in the group of patients who were evaluated by PRGS, and a PRGS ≤2 or a reduction of the mean PRGS of at least 1 between first and third PIPAC were observed in 80 %. Disease progression (50 %) or technical issues (19 %) were the most important reasons for stopping PIPAC treatment. Median overall survival from first PIPAC directed treatment varied from 10.7 months (CI 8.7-12.5) in gastric cancer to 27.1 months (16.4-50.5) in mesothelioma.

Conclusions

The ISSPP PIPAC database provides substantial real-world data supporting the use of PIPAC directed therapy in patients with PM from different primary tumors.

Targeting Adhesive Tumor Adventitia via Injectable Electrospun Short Fibers in Perfusion of Intraperitoneal Sporadic Tumors

Intraperitoneal sporadic tumor is a common and complicated syndrome in cancers, causing a high rate of death, and people find that intraperitoneal chemotherapy (IPC) can treat intraperitoneal sporadic tumors better than intravenous chemotherapy and surgery. However, the effectiveness and side effects of IPC are controversial, and the operation process of IPC is complicated. Herein, the injectable paclitaxel-loaded (PTX-loaded) electrospun short fibers are constructed through a series process of electrospinning, homogenizing, crosslinking, and subsequent polydopamine coating and folate acid (FA) modification. The evenly dispersed short fibers exhibited effective tumor cell killing and good injectable ability, which is convenient to use and greatly improved the complex operation procedure. Mussel-like protein poly-dopamine coating and FA modification endowed short fibers with the ability of targeted adhesion to tumors, and therefore the short fibers further acted as a kind of micro membrane that could release drugs to tumors at close range, maintaining local high drug concentration and prevent paclitaxel killing normal tissues. Thus, the target-adhesive injectable electrospun short fibers are expected to be the potential candidate for cancer treatment, especially the intraperitoneal sporadic tumors, which are hard to treat by surgery or intravenous chemotherapy.

CO2-Driven Nebulization of pH-Sensitive Supramolecular Polymers for Intraperitoneal Hydrogel Formation and the Treatment of Peritoneal Metastasis

Because peritoneal metastasis (PM) from ovarian cancer is characterized by non-specific symptoms, it is often diagnosed at advanced stages. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) can be considered a promising drug delivery method for unresectable PM. Currently, the efficacy of intraperitoneal (IP) drug delivery is limited by the off-label use of IV chemotherapeutic solutions, which are rapidly cleared from the IP cavity. Hence, this research aimed to improve PM treatment by evaluating a nanoparticle-loaded, pH-switchable supramolecular polymer hydrogel as a controlled release drug delivery system that can be IP nebulized. Moreover, a multidirectional nozzle was developed to allow nebulization of viscous materials such as hydrogels and to reach an even IP gel deposition. We demonstrated that acidification of the nebulized hydrogelator solution by carbon dioxide, used to inflate the IP cavity during laparoscopic surgery, stimulated the in situ gelation, which prolonged the IP hydrogel retention. In vitro experiments indicated that paclitaxel nanocrystals were gradually released from the hydrogel depot formed, which sustained the cytotoxicity of the formulation for 10 days. Finally, after aerosolization of this material in a xenograft model of PM, tumor progression could successfully be delayed, while the overall survival time was significantly increased compared to non-treated animals.

The effect of electrostatic high pressure nebulization on the stability, activity and ex vivo distribution of ionic self-assembled nanomedicines

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is applied to treat unresectable peritoneal metastasis (PM), an advanced, end-stage disease with a poor prognosis. Electrostatic precipitation of the aerosol (ePIPAC) is aimed at improving the intraperitoneal (IP) drug distribution and tumor penetration. Also, the combination of nanoparticles (NPs) as drug delivery vehicles and IP aerosolization as administration method has been proposed as a promising tool to treat PM. There is currently limited knowledge on how electrostatic precipitation (ePIPAC) and high pressure nebulization (PIPAC) affects the performance of electrostatically formed complexes. Therefore, the stability, in vitro activity and ex vivo distribution and tissue penetration of negatively charged cisPt-pArg-HA NPs and positively charged siRNA-RNAiMAX NPs was evaluated following PIPAC and ePIPAC. Additionally, a multidirectional Medspray® nozzle was developed and compared with the currently used Capnopen® nozzle. For both NP types, PIPAC and ePIPAC did not negatively influence the in vitro activity, although limited aggregation of siRNA-RNAiMAX NPs was observed following nebulization with the Capnopen®. Importantly, ePIPAC was linked to a more uniform distribution and higher tissue penetration of the NPs aerosolized by both nozzles, independent on the NPs charge. Finally, compared to the Capnopen®, an increased NP deposition was observed at the top of the ex vivo model following aerosolization with the Medspray® nozzle, which indicates that this device possesses great potential for IP drug delivery purposes. STATEMENT OF SIGNIFICANCE: Aerosolized drug delivery in the peritoneal cavity holds great promise to treat peritoneal cancer. In addition, electrostatic precipitation of the aerosol to the peritoneal tissue is aimed at improving the drug distribution and tumor penetration. The combination of nanoparticles (NPs), which are nano-sized drug delivery vehicles, and aerosolization has been proposed as a promising tool to treat peritoneal cancer. However, there is currently limited knowledge on how electrostatic precipitation and aerosolization affect the performance of electrostatically formed NPs. Therefore, the stability, activity, distribution and penetration of negatively and positively charged NPs was evaluated after aerosolization and electrostatic precipitation. Additionally, to further optimize the local drug distribution, a multidirectional spray nozzle was developed and compared with the currently used nozzle.

Smart hydrogels delivered by high pressure aerosolization can prevent peritoneal adhesions

Postoperative peritoneal adhesions occur in the majority of patients undergoing intra-abdominal surgery and are one of the leading causes of hospital re-admission. There is an unmet clinical need for effective anti-adhesive biomaterials, which can be applied evenly across the damaged tissues. We examined three different responsive hydrogel types, i.e. a thermosensitive PLGA-PEG-PLGA, a pH responsive UPy-PEG and a shear-thinning hexapeptide for this purpose. More specifically, their potential to be homogeneously distributed in the peritoneal cavity by high pressure nebulization and prevent peritoneal adhesions was evaluated. Solutions of each polymer type could be successfully nebulized while retaining their responsive gelation behavior in vitro and in vivo. Furthermore, none of the polymers caused in vitro toxicity on SKOV3-IP2 cells. Following intraperitoneal administration, both the PLGA-PEG-PLGA and the hexapeptide hydrogels resulted in local inflammation and fibrosis and failed in preventing peritoneal adhesions 7 days after adhesion induction. In contrast, the pH sensitive UPy-PEG formulation was well tolerated and could significantly reduce the formation of peritoneal adhesions, even outperforming the commercially available Hyalobarrier® as positive control. To conclude, local nebulization of the bioresponsive UPy-PEG hydrogel can be considered as a promising approach to prevent postsurgical peritoneal adhesions.

Theoretical analysis for the fluctuation in the electric parameters of the electroporated cells before and during the electrofusion

An electric pulse with a sufficient amplitude can lead to electroporation of intracellular organelles. Also, the electric field can lead to electrofusion of the neighboring cells. In this paper, a finite element mathematical model was used to simulate the distribution, radius, and density of the pores. We simulated a mathematical model of the two neighbor cells to analyze the fluctuation in the electroporation parameters before the electrofusion under the ultra-shorted electric field pulse (i.e., impulse signal) for each cell separately and after the electrofusion under the ultra-shorted pulse. The analysis of the temporal and spatial distribution can lead to improving the mathematical models that are used to analyze both electroporation and electrofusion. The study combines the advantages of the nanosecond pulse to avoid the effect of the cell size on the electrofusion and the large-pore radius at the contact point between the cells.

Graphical abstract

Electromotive Enhanced Drug Administration in Oncology: Principles, Evidence, Current and Emerging Applications

Local-regional administration of cytotoxic drugs is an important adjunct to systemic chemotherapy amongst cancer patients. It allows for targeted delivery of agents at high concentration to target sites while minimizing systemic side effects. Despite the pharmacokinetic advantages of the local-regional approach, drug transport into tumor nodules remains limited due to the biophysical properties of these tissues. Electromotive enhanced drug administration (EMDA) represents a potential solution to overcome challenges in local drug transport by applying electric currents. Through electrokinetic phenomena of electromigration, electroosmosis and electroporation, electric currents have been shown to improve drug penetration and distribution in a wide variety of clinical applications. Amongst patients with non-muscular invasive bladder cancer (NMIBC) and basal and squamous cell skin cancers, EMDA has been successfully adopted and proven efficacious in several pre-clinical and clinical studies. Its application in ophthalmological and other conditions has also been explored. This review provides an overview of the underlying principles and factors that govern EMDA and discusses its application in cancer patients. We also discuss novel EMDA approaches in pre-clinical studies and explore future opportunities of developments in this field.

Feasibility of pressurized intra peritoneal aerosol chemotherapy using an ultrasound aerosol generator (usPIPAC)

Background

We tested the feasibility of ultrasound technology for generating pressurized intraperitoneal aerosol chemotherapy (usPIPAC) and compared its performance vs. comparator (PIPAC).

Material and methods

A piezoelectric ultrasound aerosolizer (NextGen, Sinaptec) was compared with the available technology (Capnopen, Capnomed). Granulometry was measured for water, Glc 5%, and silicone oil using laser diffraction spectrometry. Two- and three-dimensional (2D and 3D) spraying patterns were determined with methylene blue. Tissue penetration of doxorubicin (DOX) was measured by fluorescence microscopy in the enhanced inverted Bovine Urinary Bladder model (eIBUB). Tissue DOX concentration was measured by high-performance liquid chromatography (HPLC).

Results

The droplets median aerodynamic diameter was (usPIPAC vs. PIPAC): H₂0: 40.4 (CI 10–90%: 19.0–102.3) vs. 34.8 (22.8–52.7) µm; Glc 5%: 52.8 (22.2–132.1) vs. 39.0 (23.7–65.2) µm; Silicone oil: 178.7 (55.7–501.8) vs. 43.0 (20.2–78.5) µm. 2D and 3D blue ink distribution pattern of usPIPAC was largely equivalent with PIPAC, as was DOX tissue concentration (usPIPAC: 0.65 (CI 5-95%: 0.44–0.86) vs. PIPAC: 0.88 (0.59–1.17) ng/ml, p = 0.29). DOX tissue penetration with usPIPAC was inferior to PIPAC: usPIPAC: 60.1 (CI 5.95%: 58.8–61.5) µm vs. PIPAC: 1172 (1157–1198) µm, p < 0.001). The homogeneity of spatial distribution (top, middle and bottom of the eIBUB) was comparable between modalities.

Discussion

usPIPAC is feasible, but its performance as a drug delivery system remains currently inferior to PIPAC, in particular for lipophilic solutions.

Phase I study of intraperitoneal aerosolized nanoparticle albumin based paclitaxel (NAB-PTX) for unresectable peritoneal metastases

Background

Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel method to treat patients with peritoneal metastases (PM). We aimed to study the tolerability, safety, pharmacokinetics, and tumour response of nanoparticle albumin bound paclitaxel (NAB-PTX) during PIPAC in a Phase I study.

Methods

Eligible patients with biopsy-proven PM from ovarian, breast, gastric, hepatobiliary, or pancreatic origin underwent three PIPAC treatments using NAB-PTX with a four-week interval. The dose of NAB-PTX was escalated from 35 to 140 mg/m² using a Bayesian design to estimate the maximum tolerated dose (MTD).

Findings

Twenty-three patients were included; thirteen (65%) patients combined PIPAC therapy with continued systemic chemotherapy. The most frequent toxicities were liver toxicity and anaemia. Treatment resulted in seven (35%) responders, six (30%) non-responders and seven (35%) patients with stable PM. Systemic absorption of NAB-PTX was slow, with median peak plasma concentrations reached after 3 to 4 h. Median NAB-PTX tumour tissue concentrations suggested accumulation: 14.6 ng/mg, 19.2 ng/mg and 40.8 ng/mg after the first, second and third PIPAC procedure respectively. EORTC QoL and VAS scores remained stable. Overall survival after one year was 57%.

Interpretation

PIPAC with NAB-PTX results in a favourable PK profile and promising anticancer activity in patients with unresectable PM. The MTD and recommended Phase II clinical trial dose are 140 mg/m². In patients with impaired hepatobiliary function, a dose of 112.5 mg/m² is recommended.

Funding

Kom op tegen Kanker (Flemish League against Cancer).

The emergence of nanoporous materials in lung cancer therapy

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer.

A two-dimensional mathematical model of tumor angiogenesis with CD147

Tumor angiogenesis is the tumor’s inherent blood supply system which is crucial for the growth of tumor. Extracellular Matrix Metallo Proteinases Inducer (EMMPRIN)/Cluster of Differentiation 147 (CD147) is found in high levels on tumor surfaces. This study focuses on these elevated levels of CD147 and the effect it has on tumor angiogenesis. The present article develops a Two-Dimensional Mathematical Model of Tumor Angiogenesis taking into account the CD147 molecule. The effects of CD147 on Tumor Angiogenesis Factors (TAFs), fibronectin and Matrix Metallo Proteinases (MMPs) are also incorporated. The results have been obtained through COMSOL Multiphysics 5.4 software. The results show that CD147 is responsible for swifter angiogenesis, calling for targeting this molecule in anti-angiogenic strategies. The present model is validated with the existing theoretical and experimental results.

Shock Response of Porcine Meniscus along with Axial and Radial Directions

The meniscus is a multifunctional fibrocartilage tissue in the knee joint which stables joint movement, bears load and absorbs impact. Improper collisions will cause damage to meniscus tissue and lose its original functionality. However, it is difficult to fully evaluate the mechanical properties of the meniscus based on static test results alone. In this study, Split Hopkinson Pressure Bar (SHPB) and hydraulic material testing system (MTS) were utilized to examine the quasi-static and dynamic properties of the porcine meniscus along with two different orientations. The results showed that the meniscus is a strain rate sensitive material and its mechanical properties mainly depend on the orientation of collagen fiber bundles in the peripheral direction. The meniscus tissue did not show obvious yield characteristics under quasi-static test conditions. However, the meniscus showed clear yield behavior under dynamic loading. When the strain rate increased, the elastic modulus of the radial meniscus remained around 35 MPa while the elastic modulus of the axial meniscus increased from 30 MPa to 80 MPa. This study demonstrates that the meniscus is sensitive to strain rate at both dynamic and quasi-static conditions, and the meniscus is an anisotropic biological tissue.

SIMULATION OF CELL MOTION IN THE MICROCHANNEL WITH A SQUARE CAVITY

Isolating circulating tumor cells (CTCs) from the blood plays an important role in the specific treatment of tumor diseases. In this study, a dissipative particle dynamics method combined with a spring-based cell model was employed to simulate the motion of a single or two cells in the microchannel with a square cavity. For a single cell with a small diameter, it will be captured by the square cavity at an appropriate flow rate. For cells whose diameter is not small enough compared to the opening size of the square cavity, they will not be captured at any flow rate. Based on this, cells of different sizes could be successfully separated when passing through this microchannel. Through the analysis of the flow behavior of uncaptured cells, the movement of cells in microchannels is divided into four stages: “guiding,” “rapid,” “slow”, and “ascending” according to the lateral movement speed and centroid position of cells. When the CTC moves together with a red blood cell, as the flow rate decreases, it would be trapped by the microcavity, whereas the RBC is not captured. Thus, CTC can be isolated from blood samples of cancer patients. The method of predicting cell movement behavior through simulation can also provide some reference for the design of microfluidic channels.

Body composition and immunonutritional status in patients treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC) for gastrointestinal peritoneal metastases: a prospective single-center analysis

Objectives

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel drug administration method with promising efficacy for the treatment of peritoneal metastases (PM). This study aimed to evaluate the prognostic value of an immunonutritional assessment on the feasibility, safety, and survival in this setting.

Methods

Data of PM patients undergoing PIPAC between September 2018 and May 2020 were prospectively recorded. A CT scan-derived body composition assessment was performed for each patient.

Results

Fifty-one patients were enrolled, of which 30 (58%) underwent multiple PIPAC cycles, with a pathological response rate of 55%. Prognostic nutritional index (PNI) and neutrophil-to-lymphocytes predicted completion of more than one PIPAC cycle, with a cut off of 36.5 and 4.8 respectively. Muscle attenuation and body fat tissues were associated with pathological response. At multivariate Cox regression analysis, only the presence of a low PNI (HR 2.41, 95% CI 1.08–5.46) was significantly associated with a worse OS.

Conclusions

A pretreatment immunonutritional assessment may provide valuable information for PIPAC patients’ selection and survival, while body composition parameters are able to predict pathological response. Further larger studies are needed to validate the role of these biomarkers in tailoring the treatment and monitoring PM patients undergoing PIPAC.

Hemodynamical analysis of MHD two phase blood flow through a curved permeable artery having variable viscosity with heat and mass transfer

A numerical investigation of MHD blood flow through a stenosed permeable curved artery has been done in this study. Blood flow is considered in two-phases; core and plasma region, respectively. Viscosity of the core region is considered as temperature-dependent, while constant viscosity is considered in plasma region. The governing equations of the proposed two-phase blood flow model are considered in the toroidal coordinate system. The second-order finite difference method is adopted to solve governing equations with [Formula: see text] tolerance in the iteration process. A comparative study of Darcy number (Da) is performed to understand the influence of permeable and impermeable wall conditions. The effect of various physical parameters such as magnetic field (M), viscosity variation parameter ([Formula: see text]), Darcy number (Da), heat source (H) and chemical reaction parameter ([Formula: see text]) is displayed graphically on the flow velocity, temperature, concentration, wall shear stress and frictional resistance profiles. A comparison with published work has also been displayed through the graph to validate the present model, and it is in fair agreement with the existing work. The present study suggested that the curvature and permeability of the arterial wall raise the risk of atherosclerosis formation, while the implication of heat source on the blood flow lower this risk.

Slug Flow Hydrodynamics Modeling for Gas–Liquid Two-Phase Flow in a Pipe

Gas–liquid flow in a pipeline is a very common. Slug two-phase flow is dominated in the case of slightly upward flow (+0.25°) and considered to be the comprehensive flow configuration, and can be in close contact with all the other flow patterns. The models of different flow patterns can be unified. Precise prediction of the slug flow is crucial for proper design and operation. In this paper, we develop hydrodynamics unified modeling for gas–liquid two-phase slug flow, and the bubble and droplet entrainment is optimized. For the important parameters (wall and interfacial friction factors, slug translational velocity and average slug length), the correlations of these parameters are optimized. Furthermore, the related parameters for liquid droplet and gas bubble entrainment are given. Accounting for the gas–liquid interface shape, hydrodynamics models, i.e., the flat interface model (FIM) and the double interface model (DIM), of liquid film in the slug body are applied and compared with the experimental data. The calculated results show that the predictions for the liquid holdup and pressure gradient of the DIM agree with experimental data better than those of the FIM. A comparison between the available experimental results and Zhang’s model calculations shows that the DIM model correctly describes the slug dynamics in gas–liquid pipe flow.

State-of-the-Art Review of The Application and Development of Various Methods of Aerosol Therapy

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

An unsteady analysis of two-phase binding of drug in an asymmetric stenosed vessel

In this paper, we investigate endovascular delivery to get a step ahead of the pharmacological limitations it has due to the complexity of dealing with a patient-specific vessel through a mathematical model. We divide the domain of computation into four sub-domains: the lumen, the lumen-tissue interface, the upper tissue and the lower tissue which are extracted from an asymmetric atherosclerotic image derived by the intravascular ultrasound (IVUS) technique. The injected drug at the luminal inlet is transported with the streaming blood which is considered Newtonian. An irreversible uptake kinetics of the injected drug at the lumen-tissue interface from the luminal side to the tissue domains is assumed. Subsequently, the drug is dispersed within the tissue followed by its retention in the extracellular matrix (ECM) and by receptor-mediated binding. The Marker and Cell (MAC) method has been leveraged to get a quantitative insight into the model considered. The effect of the wall absorption parameter on the concentration of all drug forms (free as well as two-phase bound) has been thoroughly investigated, and some other important factors, such as the averaged concentration, the tissue content, the fractional effect, the concentration variance and the effectiveness of drug have been graphically analyzed to gain a clear understanding of endovascular delivery. The simulated results predict that with increasing values of the absorption parameter, the averaged concentrations of all drug forms do decrease. An early saturation of binding sites takes place for smaller values of the absorption parameter, and also rapid saturation of ECM binding sites occurs as compared to receptor binding sites. Results also predict the influence of surface roughness as well as asymmetry of the domain about the centerline on the distribution and retention of drug. A thorough sensitivity analysis has been carried out to determine the influence of some parameters involved.

The Feasibility of Pressurised Intraperitoneal Aerosolised Virotherapy (PIPAV) to Administer Oncolytic Adenoviruses

BACKGROUND

The prognosis of patients with peritoneal metastases is poor. Treatment options are limited because systemically delivered chemotherapy is not usually effective in this type of disease. Pressurised intraperitoneal aerosolised chemotherapy (PIPAC) is a recently developed alternative technology for delivering intraperitoneal chemotherapy, potentially enhancing treatment efficacy. Here, we assess the feasibility of pressurised intraperitoneal aerosolised virotherapy (PIPAV) to deliver a different class of anticancer agents, oncolytic adenoviruses, in vitro and in vivo.

METHODS

Adenoviral vectors expressing reporter genes green fluorescence protein (Ad5.GFP) or firefly luciferase (Ad5.Luc) were subject to pressurised aerosolisation. The ability of the virus to survive PIPAV was assessed in vitro and in vivo by monitoring reporter gene activity. Wistar rats subjected to PIPAV were assessed for any adverse procedure related events.

RESULTS

In vitro transduction assays demonstrated that Ad5 retained viability following pressurised aerosolisation and could transduce permissive cells equally effectively as non-aerosolised control vector. PIPAV was well tolerated in rats, although minimal transduction was observed following intraperitoneal administration.

CONCLUSIONS

PIPAV appears viable and well tolerated, though in vivo efficacy requires further optimisation.

Temperature Distribution Simulation, Prediction and Sensitivity Analysis of Orthogonal Cutting of Cortical Bone

Bone cutting plays an important role in spine surgical operations. The power devices with high speed employing in bone cutting usually leads to high cutting temperature of the bone tissue. This high temperature control is important in improving cutting surface quality and optimizing the cutting parameters. In this paper, the bone-cutting model was appropriately simplified for finite element (FE) based modeling of 2D orthogonal cutting to discuss the change law of cutting temperature of cortical bones for cervical vertebra, and to study the orthogonal cutting mechanism of the anisotropic cortical bone, a 3D FE simulation model had been also established in which longitudinal, vertical, and transversal cutting types were accomplished to investigate the effect of osteons orientation. Secondly, this response surface method was used to regress the simulation results, and establishes the prediction model of maximum temperature on cutting depth, cutting speed, and feed speed. Then, the Sobol method was used to analyze the sensitivity of the milling temperature prediction mathematical model parameters, in order to clarify and quantitatively analyze the influence of input milling parameters on the output milling temperature. Finally, the cutting temperatures obtained with the simulations were compared with the corresponding experimental results obtained from the bone milling tests. This study verifies the influence of key variables and the cutting parameters on thermo mechanical behavior of the bone cutting. The obtained cutting temperature distribution for the bone surfaces could be employed to establish a theoretical foundation for research on thermal damage control of bone tissues.

ALTERNATIVE METHOD FOR PAIN ASSESSMENT USING EMG AND GSR

Most of the existing pain estimation techniques depend on the response of the subject through verbal or nonverbal communication which does not suit infants, senseless and injured persons, and subjects with cognitive impairment. To bridge this gap, researchers have explored the potential of facial video- and image-based pain recognition methods. However, it provides limited classification performance with complex computation and costly frameworks including a large storage capacity. The dependence of autonomic nervous system (ANS) activities on stimulus like pain provides an alternative pathway to assess pain subjected to external stimuli through ANS-related biosignals. In this article, processing and analysis technique of electromyogram and galvanic skin response signals for assessment of pain for noncooperative subjects are presented and validated against BioVid heat pain database. Different intensities of pain are considered and characterized with the statistical features extracted from the said biosignals. It is noticed that the accuracy level of pain estimation increases with the rise in pain intensity. For highest pain level, 80% detection accuracy is achieved which outperforms the performances of facial expression-based pain assessment techniques.

ONLINE ACTIVE ENSEMBLE LEARNING FOR ROBOT COLLISION DETECTION IN DYNAMIC ENVIRONMENTS

In order to improve the accuracy and precision of online learning-based collision detection methods, an online active ensemble learning for robot collision detection (OAELRCD) is proposed in this paper. The OAELRCD consists of two key components: (1) an ensemble learning method to combine several base classifiers in order to improve the accuracy and precision of collision detection, (2) an active learning algorithm to reduce the number of training samples in order to realize online training and learning when the environment changes. We evaluate the proposed OAELRCD on one robot arm in dynamic environments with moving workspace obstacles, showing that the proposed OAELRCD outperforms state-of-the-art online learning-based method and geometric collision checkers. Compared to the state-of-the-art online learning-based method for robot collision detection in dynamic environments, the proposed OAELRCD provides noticeable improvements in TPR, AUC, Accuracy and TNR. Compared to state-of-the-art geometric collision checkers, with the proposed OAELRCD, collision checks are faster.

Therapeutic efficacy and cardioprotection of nucleolin-targeted doxorubicin-loaded ultrasound nanobubbles in treating triple-negative breast cancer

Targeted lipid nanobubbles as theranostic ultrasound molecular probes with both targeted contrast-enhanced ultrasound molecular imaging and synergistic treatment capabilities are expected to overcome severe challenges in the diagnosis and treatment of refractory triple-negative breast cancer (TNBC). In this study, AS1411 aptamer-functionalised nucleolin-targeted doxorubicin-loaded lipid nanobubbles (AS1411-DOX-NBs) were constructed, and their physicochemical properties as well as anti-tumour and cardioprotective efficacies were systematically tested and evaluated. The results showed that AS1411-DOX-NBs can carry and maintain the physicochemical and pharmacodynamic properties of doxorubicin (DOX) and show stronger tumour cell-killing abilityin vitroby increasing the active uptake of drugs. AS1411-DOX-NBs also significantly inhibited the growth of TNBC xenografts while maintaining the weight and health of the mice. Echocardiography and pathological examination further confirmed that AS1411-DOX-NBs effectively caused tumour tissue apoptosis and necrosis while reducing DOX-induced cardiotoxicity. The AS1411-DOX-NBs constructed in this study enable both targeted contrast-enhanced ultrasound molecular imaging and synergistic therapeutic efficacy and can be used as safe and efficient theranostic ultrasound molecular probes for the diagnosis and treatment of TNBC.