Literature Review of Laponite

Biomedical applications of Laponite

The drug delivery system can be controlled and sustained by different mesoporous inorganic particles. The delivery of drugs is based on the different morphologies including (nanotubes, nanoplates, and nanofibers). The process is applicable due to the efficient delivery of drug and cost effective process¹. The surfaces can be modified by different release properties and synthetic nanomaterials include mesoporous silica, laponite, and imogolite. The advantages are featured sizes that can be controlled¹.   

1.      Laponite-based drug delivery systems at the nanoscale

The research conducted by Mustafa is about the functionalized Laponite nanodisk that is used for the drug delivery process². The research was conducted for the delivery of anticancer drug doxorubicin (DOX). The modification of Laponite was based on the silence coupling agents associated with the succinic anhydride that were rendered and abundant groups of carboxyl over the surface of the LAP. The conjugated process was used for the dendrimered generation of G2 and poly (amidoamine) (PAMAM) for the formation of LM-G2 nanodisks². The drugs of DOX were loaded to the nanodisks LM-G2 and drug loading efficiency was measured at 98.4%. The cell viability indicated in the LM-G2/DOX is complex due to sustained manner sensitivity of pH. The complex and effective inhabitation is carried out by the proliferation of epithelial carcinoma cells².

 The free DOX concentration is used in drug processing. The KB cells were used effectively for uptaking of LM-G2/DOX as compared to the free DOX and analysis were carried out by flow cytometry and confocal laser scanning microscope. The researchers used the research for the efficient drug loading process for the amine groups and it was used for the novel platform related to the delivery of anticancer drugs². The modification of APMES and LAP nanodisk were done by changing weight through variation of temperature from 200 to 600C. The synthesis was done by changing the temperature from 25 to 60C through absorption of moisture².     

Yilun Wu and his research group conducted research for modification of folic acid laponite nanodisks and the targets for the drug delivery were cancer cells. The approach for the laponite nanodisks (LAP) was done by the modification of 3-aminopropyldimethlyethoxysilane (APMES) over the surfaces of amines³. The second process of conjugation of the FA through the 1-ethyl-3-(3-dimethylaminopropyl) carbo-di-imide (EDC). The modified form of FA-modified LAP nanodisks (LM-FA) was then used for the DOX. In the present situation, DOX stands for the encapsulated drug doxorubicin (DOX) for the anticancer cells³.

The surface modifications for the drug delivery was then characterized by various techniques. The efficiency for the DOX was 92.1% and the complexity was determined by the pH conditions under different acidic conditions for pH conditions³. The therapeutic conditions were analyzed for the higher affinity of the laponite. The cancer cells were considered for the receptors of FA. The characteristic was determined by the confocal microscope and through flow cytometric analysis. The development of modified LAP nano disks was to deliver the drug for different targets of anticancer cells³.     

2.      Laponite-polymer hydrogel/scaffold drug delivery systems

The research conducted by Taigo B. Becher and his coworkers was based on the drug delivery of nanohydrogels through the laponite nanodiscs. The main purpose was theranostic drug delivery by flexible nanohydrogels. The study was in vitro demonstration of nano hydrogels that are noncytotoxic, nonswellable, biocompatible, pH-responsive, and biodegradable ⁴.

The nanohydrogels of IC₅₀ contained cyclophosphamide along with the 4-fluorouracial. The simple formulism was used for the chemical modifications and versatile delivery system of nanohydrogels. The Laponite XLG was formed by Sodium polyacrylate, cyclohexane, WST-8, 4-fluorouracil and cyclophosphamide⁵. The synthesis was carried out by the formalism of nanohydrogels NHGI-NHG4, nanodisc solution for NHG4, NHG3, and NHG2, and NHG5-NHG8.

The nanohydrogels were formed by the laponite aqueous solutions and nanodiscs were formed by the sonication of NHG6, NHG7, and NHG8. The formation of nano hydrogels NHG9 was characterized by cell culture, Rheology, cryogenic transmission electron microscopy (Cryo-TEM)⁵. The size of laponite was determined by dynamic light scattering and nanoparticle tracking system (NTA). The drug delivery was determined by the cytotoxicity and nanohydrogels that contained NHG2, NHG3, as well as NHG4⁵.

 The composition of the carrier was optimized by nanogels consisting of 96% (w/w) water, 1.0% (w/w) sodium phosphate salts, 0.5% (w/w) polyacrylic acid, and 2.5% (w/w). The Hela cells and the incubating cells were analyzed by the flow cytometry and fluorescence intensity was determined for all the components⁵. 

The research conducted by ⁶ was based on the model formalism of magnetically responsive hydrogels. The responsiveness of hydrogels through the radical polymerization was for the carboxymethyl cellulose and potassium persulfate (KPS)⁶. The evaluation of drug loading and the drug release efficiency was carried out by the model drug of Diclofenac sodium (DS). The rough morphology was measured by the SEM analysis and magnetic nanoclay (MMT). The pH of the applied magnetic field was 7.4 and the cumulative release was 79%. The drug delivery was determined by the colon of hydrogels⁶.  

In 2014, Divya Bhatnager and his research group ⁷ measured the control drug delivery and the cell adhesion for the hyaluronic acids. The laponite hydrogels were mechanically stable and used for the transparent delivery of drugs. The hydrogels were obtained by the HA-gelatine and polymer ratio was increased as compared to the clay ratio⁷. The fibroblast adhesion was observed for the stiffer substrate and showed modulus of the hydrogels. The detailed analysis was determined by the rheological characterization for the controlling parameter of the drug in the hydrogels. The drug delivery was analyzed using the gelatin cross linkage with the Laponite and the ion exchange process⁷.

The laponite in the analysis was intercalated by the gelatin and was composed of inorganic synthetic disk like particles. The effectivity of the drug delivery was determined by the exfoliation, swell ability, purity, sufficient platelet size, and properties of the biopolymers. The cross linkage was designed for the HA clay, HA gelatin, and stiffness of the scaffold⁷. The cross linkage in the chitosan and the PEO was measured by the inject ability of the hydrogels. The soft and the hard hydrogels were manufactured by the different densities. The polymers based on the Laponite were composite hydrogels and showed reliable barriers for the sustained delivery of the drugs⁷.

The layered silicates were used for the formation of the platelets by the exfoliation. The formation of the HA-Clay, HA gelatin clay, and the gelatin clay was entangled with the chains of polymers and the gelain absorption. The sodium clay was used for the formation of the HA clay hydrogels⁷.       

The research conducted by ⁸ was about the nanocomposite hydrogels along with the applications for drug delivery in the tissues. The properties improved in the NC gels included tunable cell adhesion, biodegradability, and the biocompatibility. The synthesis of hydrogels was carried out by the N-isopropyl acrylamide and the hydrogel matrix⁸. The unique structures were proposed by the proper dispersed and exfoliation of the drugs. The three dimensional cells were hMSC and the two dimensional cells were PEG diacrylate (PEGDA) by the laponite NC gels. The hydrogel system was developed for the injectable system 3D PEG and the encapsulated cells⁸.     

Figure 2: Laponite-polymer hydrogel/scaffold drug delivery systems

3.      Laponite as a modulator of gel/scaffold mechanical

The hydrogels were developed actively for the controlled delivery of drugs and through the clinical translation⁹. The analysis includes limited loading of drugs, storage stability, and loading capacity. The work reported complete design for the hydrogels and translational perspectives of the hydrogels. The large surface areas were used for the feasibility of composite hydrogels. In the analysis, the large quantities were developed for the demonstration of the feasibility and the mimetic protein growth⁹. The approach was potential applications and the delivery process for the local controlling. The scaffold was determined by the composite hydrogels and used surgical implantation of the Achilles tendon injury¹⁰. 

The Achilles tenotomy treated drug releasing scaffolds with the composite hydrogels. The implantation process was confined to the distribution of drugs in the tendons⁹. The scattering method was used for the extreme composite hydrogels and reduced the systematic factors of growth factors. In the final concentration of the scaffold laponite, the calcium sulfate was 3.6%, and lypophilization of the hydrogels were carried out for 6 hours at the optimized temperature of the 80C⁹.   

Figure 3: Laponite as a modulator of gel/scaffold mechanical

Review of Laponite

A number of researchers worked for the covalent and the non-covalent functionality of the Laponite. The composition depends on the reactive groups including primary amines, benzophenones, tertiary bromines, and methacrylates¹¹. The formation of the gel enables self-heating and the reversibility of the non-covalent bonds.

The functionality of the Laponite can be obtained by the q-PDMAEMA and poly 2 dimethylamino ethyl methacrylate. The drug delivery at the nanoscale level was due to the efficiency of the crystals¹¹. The cytotoxicity of the cancer cells was higher in the solution of phosphate buffered saline. In the process of loading the doxorubicin on the laponite crystals, two different types of polyelectrolyte polymers were used.

The approach was an extension in the drug release due to polyelectrolytes. The drug delivery rates were associated with the sensitivity of the environment. The disks of laponite were used for the doxorubicin functionality¹¹. The hydrophilic polymers were considered for the water soluble polymers and sensitivity was based on the thermal properties and the pH sensitivity. The response properties were based on the magnetic field, temperature and the pH of the drugs. The hybrid hydrogels were used for the minimization of the acidic environment¹¹.

The sensitivity of the hydrogel polymers was based on the ionic cross linking process of sodium tri-polyphosphate (TPP). The research was focused on the nono composite hydrogels that are efficient in drug delivery due to nano-filler in the NC gels. The functionality of synthetic nanoparticles is related to the features of stimuli responsiveness¹¹.