Light-Activated Systems
Light can be used as an external stimulus since its intensity can be precisely controlled. Light- sensitive materials have been used a lot as drug delivery systems. These delivery systems
Table 9.2 Stimuli-sensitive nanofiber delivery systems in pharmaceutical and biomedical applications
|
Stimulus |
Active moiety |
Polymer |
Target diseases |
Comments |
References |
|
pH |
Doxorubicin |
Silk |
Breast cancer |
Thixotropic silk hydrogels provide improved injectability to support sustained release, suggesting promising applications for localized chemotherapy |
[20] |
|
Doxorubicin |
Poly (e-caprolactone) (PCL) |
Gastric cancer and vaginal delivery of antiviral drugs or antiinflammatory drugs |
The pH-responsive drug delivery systems based on PCL nanofibers have the potential in oral delivery of anticancer drugs for treating gastric cancer and vaginal delivery of antiviral drugs or antiinflammatory drugs, to deliver them to the specific target, and minimize their toxic side effects |
[21] |
|
|
Etravirine and TDF |
Cellulose acetate phthalate (CAP) |
Human immunodeficiency virus (HIV) |
The pH-dependent release properties have been carefully studied and we show that the released antiviral drugs, together with the CAP, which has been reported to have intrinsic antimicrobial activity, efficiently neutralize HIV in vitro |
[22] |
|
|
Polyurethane (PU) and CAP |
HIV |
CAP imparts pH responsiveness to the core—shell structure giving the fibers potential for semen sensitive intravaginal drug delivery |
[23] |
||
|
Paracetamol |
Triblock copolymers |
Various applications |
The local delivery and controllable release profiles make these fibers as potential implantable drug carriers and functional coatings of medical devices |
[24] |
|
Temperature |
Paclitaxel |
PCL |
Liver cancer |
The approach developed here uses the nanofibers and nanoparticles together for the treatment of cancer |
[25] |
|
Ibuprofen |
Poly(N- isopropylacrylamide) and PCL |
Various applications |
Composite design can provide a novel approach to suppress the burst effect in drug delivery systems for potential pharmaceutical applications |
[26] |
|
|
Ketoprofen |
Poly(N- isopropylacrylamide), ethyl cellulose |
Various applications |
This study demonstrated that electrospun-blend PNIPAAm/EC fibers comprise effective and biocompatible materials for drug delivery systems and tissue engineering |
[27] |
|
|
Light |
Polymethylmethacrylate (PMMA) nanofibers doped with silver nanoparticles (AgNPs) and meso- tetraphenylporphyrin (TPP) |
PMMA nanofibers doped with AgNPs and TPP |
Antibacterial |
Results suggest that the proposed material is a promising option for the photodynamic inactivation of bacteria |
[28] |
|
Fluorescein isothiocyanate—bovine serum albumin |
poly(N- isopropylacrylamide- co-polyethylene glycol acrylate) |
These results suggest that light- responsive fibrous nanocomposites can be utilized in applications such as drug delivery |
[29] |
||
|
Moisture |
Maraviroc |
Polyvinylpyrrolidone or poly(ethylene oxide) |
HIV |
Water-soluble electrospun materials can rapidly release maraviroc upon contact with moisture and that drug delivery is faster (less than 6 min under sink conditions) when maraviroc is electrospun in polyvinylpyrrolidone fibers containing an excipient wetting agent |
[30] |
Continued
Table 9.2 Stimuli-sensitive nanofiber delivery systems in pharmaceutical and biomedical applications—cont'd
|
Stimulus |
Active moiety |
Polymer |
Target diseases |
Comments |
References |
|
Hydrogen peroxide |
Rhodamine B |
Polyvinyl alcohol (PVA)/p olyoxalate (PVA/POX NFs) blended |
Inflammatory diseases |
Nanofibrous PVA/POX can potentially be used to target numerous inflammatory diseases that overproduce hydrogen peroxide and may become a potential candidate for use as a local drug delivery vehicle |
[31] |
|
pH + glucose |
Lectins |
ConA andJacalin |
Removal of toxins from the solution |
These functional nanofibers can therefore be easily modified and hence can be used for quick removal of selective proteins or toxins from the solution |
[32] |
|
pH + temperature |
Nifedipine (NIF) |
Poly(N- isopropylacrylamide)- co-poly(acrylic acid) [P(NIPAAm- co-AAc)] |
The release amount of NIF from the nanofibers could be controlled effectively by adjusting the temperature or pH value of the aqueous medium and incorporating the hydrophobic PU |
[33] |
Electrospun Nanofibers in Drug Delivery 199
Figure 9.3 Triggered drug release from nanofiber in the presence of various stimuli.
incorporate light-sensitive groups such as azobenzene, stilbene, and triphenylmethane into the formulation, which respond to a specific wavelength. The light-sensitive polymers are hydrophilic, biocompatible, and biodegradable. However, the limitations of light-sensitive polymers include inconsistent response due to leaching of chromophores during swelling or contraction of the system, and a slow response is achieved with stimulus. These polymers can be divided into ultraviolet (UV)- and visible light-sensitive systems on the basis of the wavelength that triggers the phase transition. Visible light-sensitive polymers are preferred over UV-sensitive polymers because of their availability, safety, and ease of use [19,36,37].
