Imperial College London

DrAsadJamal

Faculty of EngineeringDepartment of Mechanical Engineering

 
 
 
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Contact

 

a.jamal

 
 
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Location

 

City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

6 results found

Yuan T, Zhan W, Jamal A, Dini Det al., 2022, On the microstructurally driven heterogeneous response of brain white matter to drug infusion pressure, Biomechanics and Modeling in Mechanobiology, Vol: 21, ISSN: 1617-7959

Delivering therapeutic agents into the brain via convection-enhanced delivery (CED), a mechanically controlled infusion method, provides an efficient approach to bypass the blood–brain barrier and deliver drugs directly to the targeted focus in the brain. Mathematical methods based on Darcy’s law have been widely adopted to predict drug distribution in the brain to improve the accuracy and reduce the side effects of this technique. However, most of the current studies assume that the hydraulic permeability and porosity of brain tissue are homogeneous and constant during the infusion process, which is less accurate due to the deformability of the axonal structures and the extracellular matrix in brain white matter. To solve this problem, a multiscale model was established in this study, which takes into account the pressure-driven deformation of brain microstructure to quantify the change of local permeability and porosity. The simulation results were corroborated using experiments measuring hydraulic permeability in ovine brain samples. Results show that both hydraulic pressure and drug concentration in the brain would be significantly underestimated by classical Darcy’s law, thus highlighting the great importance of the present multiscale model in providing a better understanding of how drugs transport inside the brain and how brain tissue responds to the infusion pressure. This new method can assist the development of both new drugs for brain diseases and preoperative evaluation techniques for CED surgery, thus helping to improve the efficiency and precision of treatments for brain diseases.

Journal article

Jamal A, Yuan T, Galvan S, Castellano A, Riva M, Secoli R, Falini A, Bello L, Rodriguez y Baena F, Dini Det al., 2022, Insights into infusion-based targeted drug delivery in brain: perspectives, challenges and opportunities, International Journal of Molecular Sciences, Vol: 23, Pages: 3139-3139, ISSN: 1422-0067

Targeted drug delivery in the brain is instrumental in the treatment of lethal brain diseases, such as glioblastoma multiforme, the most aggressive primary central nervous system tumour in adults. Infusion-based drug delivery techniques, which directly administer to the tissue for local treatment, as in convection-enhanced delivery (CED), provide an important opportunity; however, poor understanding of the pressure-driven drug transport mechanisms in the brain has hindered its ultimate success in clinical applications. In this review, we focus on the biomechanical and biochemical aspects of infusion-based targeted drug delivery in the brain and look into the underlying molecular level mechanisms. We discuss recent advances and challenges in the complementary field of medical robotics and its use in targeted drug delivery in the brain. A critical overview of current research in these areas and their clinical implications is provided. This review delivers new ideas and perspectives for further studies of targeted drug delivery in the brain.

Journal article

Jamal A, Bernardini A, Dini D, 2022, Microscale characterisation of the time-dependent mechanical behaviour of brain white matter, JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, Vol: 125, ISSN: 1751-6161

Journal article

Jamal A, Mongelli M, Vidotto M, Madekurozwa M, Bernardini A, Overby D, De Momi E, Rodriguez y Baena F, Sherwood J, Dini Det al., 2021, Infusion mechanisms in brain white matter and its dependence of microstructure: an experimental study of hydraulic permeability, IEEE Transactions on Biomedical Engineering, Vol: 68, Pages: 1229-1237, ISSN: 0018-9294

Objective: Hydraulic permeability is a topic of deep interest in biological materials because of its important role in a range of drug delivery-based therapies. The strong dependence of permeability on the geometry and topology of pore structure and the lack of detailed knowledge of these parameters in the case of brain tissue makes the study more challenging. Although theoretical models have been developed for hydraulic permeability, there is limited consensus on the validity of existing experimental evidence to complement these models. In the present study, we measure the permeability of white matter (WM) of fresh ovine brain tissue considering the localised heterogeneities in the medium using an infusion based experimental set up, iPerfusion. We measure the flow across different parts of the WM in response to applied pressures for a sample of specific dimensions and calculate the permeability from directly measured parameters. Furthermore, we directly probe the effect of anisotropy of the tissue on permeability by considering the directionality of tissue on the obtained values. Additionally, we investigate whether WM hydraulic permeability changes with post-mortem time. To our knowledge, this is the first report of experimental measurements of the localised WM permeability, showing the effect of axon directionality on permeability. This work provides a significant contribution to the successful development of intra-tumoural infusion-based technologies, such as convection-enhanced delivery (CED), which are based on the delivery of drugs directly by injection under positive pressure into the brain.

Journal article

Jamal A, Nyrkova I, Mesini P, Militzer S, Reiter Get al., 2017, Solvent-controlled reversible switching between adsorbed self-assembled nanoribbons and nanotubes, NANOSCALE, Vol: 9, Pages: 3293-3303, ISSN: 2040-3364

Journal article

Shokri R, Guskova O, Jamal A, Jahanshahi K, Isare B, Bouteiller L, Simon L, Sommer J-U, Reiter Get al., 2015, Consequences of a Single Double Bond within a Side Group on the Ordering of Supramolecular Polymers, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 119, Pages: 22596-22603, ISSN: 1932-7447

Journal article

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