Specific Application of LbL Microcarriers in Drug Delivery

  • Specific Application of LbL Microcarriers in Drug Delivery

Specific Application of LbL Microcarriers in Drug Delivery

Another objective is the development of specific drug delivery systems such as a combined transport and sensor system for anti-inflammatory substances (AIS). The layer-by-layer coated carriers are intended to transport and release a defined amount of AIS into the inflamed tissue in order to terminate chronically proceeding processes and to facilitate the regeneration of tissue homeostasis. The simultaneous release of AIS into the phagolysosomes of polymorphonuclear leukocytes (PMNs) as well as into the extracellular space is a new approach for an effective inhibition of pro-inflammatory substances originating from these cells and macrophages. In particular, anti-protease 1-antitrypsin was transported by LbL microcarriers to inhibit the protease elastase at its place of origin.

Focus on:

  • Design of specific LbL-based transport systems for AIS

    • defined amounts of  a1-antitrypsin as multilayer constituent
    • parallel integration of additional substances and sensors
    • LbL particles and LbL capsules

  • Carrier/cell interaction: PMNs

    • fast carrier uptake
    • fast multilayer disassembly within phagolysosomes and AIS release
    • efficient intracellular elastase inhibition
    • intra- and extracellular elastase inhibition combined in one carrier
    • negligible carrier effect on cell vitality

  • Carrier/cell interaction: macrophages

    • negligible carrier effect on cell vitality
    • no carrier-induced pro-inflammatory signaling

1. Carrier Design

For an application in PMNs, LbL microcarriers have to be built up by an internally easily degradable multilayer and facilitate the integration of a defined amount of AIS.

The amount and activity of 1-antitrypsin (AT) essential for the inhibition of intracellular elastase can be determined in concentration-dependent studies of AT/elastase interaction under phagolysosomal and extracellular conditions(1) by means of spectrophotometry. Under ideal conditions, the assembly of AT as only one outer layer of the biopolymer multilayer and the application of one carrier per cell is sufficient to efficiently inhibit intracellular elastase(2). Extending the experiments towards capsules, coating conditions of AT have to be adapted to the dissolution procedure of the core material, since this treatment may influence the amount and activity of AT as previously assembled multilayer constituent(3).

 

(1)   Schönberg, M., Reibetanz, U.,  Rathmann, S., Leßig, J. Maintenance of  α1-antitrypsin activity by means of co-application of hypochlorous acid scavengers in vitro and the supernatant of polymorphonuclear leukocytes - As  a basis for a new drug delivery approach. Biomatter 2 (2012) 1-13. [PubMed]

(2)   Reibetanz, U., Schönberg, M., Rathmann, S., Strehlow, V., Göse, M., Leßig, J. Inhibition of Human Neutrophil Elastase by Alpha1-Antitrypsin Functionalized Colloidal Microcarriers. ACS Nano 6 (2012) 6325-5336. [DOI]

(3)   Strehlow, V., Leßig, J., Göse, M., Reibetanz, U. Development of LbL-biopolymer capsules as delivery system for the multilayer-assembled anti-inflammatory substance α1-antitrypsin. J. Mater. Chem B. 1 (2013), 3633–3643 [DOI]

 

 

2. Carrier/PMN Interaction

 The functionalized microcarriers are then applied as drug transport and delivery systems for AT addressing PMNs (isolated from blood) and PMN-like differentiated U 937(4). Compared to other applications, the intracellular target here is already the phagolysosome, since after phagocytosis a fusion of carrier-containing phagosomes and enzyme-containing granules and lysosomes occurs followed by enzyme triggered multilayer disassembly, release of anti-protease AT and subsequent elastase inhibition. However, those carriers have to undergo a very fast uptake in order to disassemble and release the agents during the very short PMN's life time of about 24 h(5).

Using the same construction, extracellular remaining AT-functionalized carriers are capable of inhibiting already released elastase in parallel to the internalized carriers. The non-internalized carriers immobilize the protease on their surfaces by AT/elastase complexation(6).

Additionally to their transport abilities, the LbL carriers themselves are intended to have only low negative influence on cell viability, i.e. on apoptosis or necrosis characteristics. In this context, AT functionalized LbL carriers even induce a positive effect on PMN’s vitality by delaying apoptosis(7).  

In parallel to LbL-mediated AT transport, the efficiency of a cell-penetrating peptide (CPP)-mediated AT administration was investigated comparing advantages and disadvantages of both carrier systems (8)

 

(4)   Leßig J, Neu B, Glander H-J, Arnhold J, Reibetanz U. Phagocytotic Competence of Differentiated U937 Cells for Colloidal Drug Delivery Systems in Immune Cells. Inflammation 34 (2011) 99-110.  [DOI, PubMed].

(5)   Rathmann, S., Schönberg, M., Leßig, J., Reibetanz, U. Interaction, Uptake and Processing of LBL-coated Microcarriers by PMNs. Cytom. Part A 79 (2011) 979-989. [PubMed]

(6)   Reibetanz, U., Schönberg, M., Rathmann, S., Strehlow, V., Göse, M., Leßig, J. Inhibition of Human Neutrophil Elastase by Alpha1-Antitrypsin Functionalized Colloidal Microcarriers. ACS Nano 6 (2012) 6325-5336. [DOI]

(7)   Fichtner, M., Claus, C., Lessig-Owlanj, J., Arnhold, J., Reibetanz, U. The Application of LbL-Microcarriers for the Treatment of Chronic Inflammation: Monitoring the Impact of LbL-Microcarriers on Cell Viability. Macromol. Biosci. (2015) 546-557.[PubMed]

(8)   Leßig, J., Reibetanz, U., Schönberg, M., Neundorf, I. Efficient Inhibition of Human Leukocytic Elastase by means of Alpha1-Antitrypsin/Peptide Complexes. Cytometry: Part A 83 (2013) 461-471. [DOI]

 

 

3. Carrier/Macrophage Interaction

Beside the carrier interaction with PMNs, the role of macrophages regarding the clearance of apoptotic or necrotic PMNs and microcarriers has to be considered. In particular, the carriers are not intended to induce pro-inflammatory signalling of macrophages. Experiments regarding cell interaction with colloidal microparticles as well as with microcapsules show only a very low negative influence on the cells(9,10).

 

 

(9)    Leßig, J., Neu., B., Reibetanz, U. Influence of Layer-by-Layer (LbL) Assembled CaCO3-Carriers on Macrophage Signaling Cascades. Biomacromolecules 12 (2011) 105-115. [PubMed]

(10)  Strehlow, V., Leßig, J., Göse, M., Reibetanz, U. Development of LbL-biopolymer capsules as delivery system for the multilayer-assembled anti-inflammatory substance α1-antitrypsin. J. Mater. Chem B. 1 (2013), 3633–3643 [DOI]

Funding

  • Translational Center for Regenerative Medicine, Leipzig, German Federal Ministry of Education and Research (BMBF, PtJ-Bio, 0313909); Co-Investigator: Dr. J. Lessig
  • German Research Foundation (DFG, RE 2681/2-1)
  • German Research Foundation (DFG, RE 2681/2-2)
letzte Änderung: 08.06.2017