The following article is an edited transcript of the Von Hippel Award address, given by recipient Larry L. Hench at the 1998 MRS Fall Meeting on December 3, 1998. Hench received the Materials Research Society's highest honor for “pioneering accomplishments in the field of glass and ceramics, including the demonstration of the first bioactive glass called Bioglass® and subsequent expansion of the field, demonstration of the feasibility of encapsulating nuclear waste products in glass/ceramic matrices, and development of sol-gel processing to produce ultrahigh-purity optical and dielectric materials with controlled microstructures.”

The problem our Society faces as we head into the next millennium is that our average age expectancy has increased to a very attractive number of years but our bodies begin to deteriorate long before then. With the use of antiseptics, anti-biotics, and vaccinations during this Century, we have increased our survival rate considerably, as shown in Figure 1. The average age expectancy has increased to the mid-70s for many countries. However, as we pass the age of 30, our bodies begin to deteriorate. The quality of our connective tissues, particularly our skeletal tissues that hold us upright, begins to decline. The volume of bone that Supports us decreases with time, and for at least some of us, the weight our bones have to bear increases with time. The net effect is that the strength of bone degrades with age, causing the probability of fracture to increase (Figure 2). lf we integrate the area under the curve in Figure 1 from 60 years onward to 90 years, multiply it by the couple of billion people on earth, and then multiply that by the fraction of people subject to bone failure (Figure 2), we have a catastrophic repair problem facing society.

The following is an edited transcript of the presentation given by H. Eugene Stanley (Boston University), recipient of the MRS 1998 David Turnbull Lectureship, at the 1998 MRS Fall Meeting on December 2,1998, in Boston.

I would like to begin with a kind of kitchen experiment that any of you can do. Take your favorite drink. For some, this is ice water (Figure 1). Ask a simple question: “Whatshould this thermometer read?” And think for a minute of the implications of the answer to your question.

The title of this talk concerns water in two different states: the liquid State and the glass State. We'll organize this talk around three questions:

■ “What is the puzzle of liquid water?”

■ “Why do we care about this puzzle?”

■ “What do we actually do?”

The “we” in this case is a rather large number of individuals. TU focus this talk on very recent work that has been published or at least submitted this year. This work was done in collaboration with M.-C. Bellissent-Funel, S.V. Buldyrev, M. Canpolat, M. Meyer, O. Mishima, M.R. Sadr-Lahijany, A. Scala, and F.W. Starr. It's also based on earlier research a few years back with C.A. Angell, P.G. Debenedetti, A. Geiger, P.H. Poole, S. Sastry, F. Sciortino, and J. Teixeira. Any of these 15 valued collaborators could probably give this talk as well as, if not better than, I will.

We will organize the answer to our third and principal question in the following way: First, we will attempt to identify, in the spirit of Sherlock Holmes, some interesting clues.

It is widely recognized that the presence of defects in crystals and other solid materials can have a profound effect upon their chemical and physical properties and, consequently, that defects have a major impact on the practical utility of many technological materials. The presence of defects in a crystalline material implies the presence of disorder, and the extent of such disorder can range from very minor, such as the occurrence of Schottky defects in a crystal of sodium chloride, to maximum disorder, as in an amorphous material. The focus of this overview is on systems that are partially disordered, spanning the range between—but not including—sodium chloride and an amorphous material. Even within this range, the aim is not to be comprehensive, since for space reasons we have restricted our coverage to inorganic materials and hybrid inorganic-organic systems. The choice of this topic stems from both its fundamental and practical importance; it is also a very timely topic. For example, there is a great deal of current interest in complex, partially ordered materials such as the surfactant-mediated mesoporous silicas, biominerals, and hybrid organic-inorganic composites. Research on such materials has presented challenges that cannot easily be addressed by characterization tools that have been developed for well-ordered materials. The same situation is found in other areas such as carbons (including nanotubes) and glassy metal oxides.

The development of biomaterials to treat, repair, or reconstruct the human body is an increasingly important component of materials research. Collaboration between materials researchers and their industrial and clinical partners is essential for the development of this complex field. To demonstrate the importance of these interactions, two articles in this issue focus on advances in biomaterials relating to the use of colloidal systems for transport, drug delivery, and other medical applications. These articles were coordinated by Dominique Muster (Université Louis Pasteur, Strasbourg) and Franz Burny (Hôpital Erasme, Brussels). The following is the first of these two articles.

A large variety of colloidal Systems involving highly fluorinated components have been prepared and investigated in recent years. These fluorinated Systems comprise diverse ty pes of emulsions (e.g., direct, reverse, and multiple emulsions; microemulsions; gel emulsions; waterless emulsions) with a fluorocarbon phase (and often a fluorinated Surfactant), and a ränge of self-assemblies (vesicles, tubules, helices, ribbons, etc.) made from fluorinated amphiphiles. Fluorinated Langmuir films and fluorinated black lipid membranes (BLMs) also have been investigated.

Research in this area was driven by the potential applications of such materials in medicine and biology. Fluorocarbon-based products are being developed as injectable oxygen carriers (“blood Substitutes”), media for liquid Ventilation, drug delivery Systems, and contrast agents for ultrasound imaging. One such agent has recently been approved for use in Europe and the United States. Several more products are in an advanced stage of clinical evaluation, and others are in various stages of preclinical development. From a more fundamental Standpoint, these materials are being investigated for assessing and understanding the impact that fluorinated components have on the formation, stability, structure, and properties of colloida l Systems in comparison with their hydrocarbon counterparts. The attention given to fluorinated colloids prompted the synthesis of numerous new families of fluorinated amphiphiles, which were to become components of such colloids.

The development of biomaterials to treat, repair, or reconstruct the human body is an increasingly important component of materials research. Collaboration between materials researchers and their industrial and clinical partners is essential for the development of this complex field. To demonstrate the importance of these interactions, two articles in this issue focus on advances in biomaterials relating to the use of colloidal systems for transport, drug delivery, and other medical applications. These articles were coordinated by Dominique Muster (Université Louis Pasteur, Strasbourg) and Franz Burny (Hôpital Erasme, Brussels). The following is the second of these two articles.

There are two important objectives in drug delivery research. The first is to maximize the effectiveness of drugs by increasing the amount of drug reaching the target tissue while sparing other tissues the deleterious effects of the drug. The second is to control the release of a drug, so that the period of optimal drug concentration in the target tissue is maximized. A numbe r of different Systems have been investigated to achieve these objectives, including soluble polymeric delivery Systems and a range of colloidal drug delivery forms such as liposomes, emulsions, micelles, microcapsules, microparticles, and nanoparticles. This article focuses on polymeric materials for the production of micro- or nanoparticle Systems for dru g delivery by injection, and their characterization and Performance in vivo.

Colloidal particles have a number of advantages as drug delivery Systems; they are easy to prepare, have the potential for high drug loading, and release of the drug can be controlled. However, without surface modification, colloidal particles are difficult to target because they are directed largely to the liver and spieen after intravenous injection. The reasons for this can be found in the context of the body's defenses. In order to protect against disease, the body has a complex System to ensure that invading microorganisms are identified and neutralized at the earliest possible opportunity. Most parasitic or invading organisms which pose a threat are particulate in form, and thus any colloidal drug delivery System will have to evade detection by these mechanisms in order to reach its target.